declare @t table(ID int ,[Name] varchar(10)) insert @t select 1,null insert @t select 2,'A' insert @t select 3,'C' insert @t select 4,'' select ID,isnull([Name],'')[Name] from @t /*ID Name ----------- ---------- 1 2 A 3 C 4 */
统计函数和建视图 跟SQL Server基本是一样的。有Oracle论坛,为啥跑这里问?
发的时候没注意,发到SQL这来了,现在又发不过去了...
如果输入的是空的,那么显示在页面不可能是空格.是个null值.
oracle中建视图和sql server中基本一样.例如:create view my_view as select a.* , b.* from a,b where a.id = b.id
以下为oracle和sql常用函数的比较.SQLServer和Oracle的常用函数对比
1.绝对值 S:select abs(-1) value O:select abs(-1) value from dual 2.取整(大) S:select ceiling(-1.001) value O:select ceil(-1.001) value from dual 3.取整(小) S:select floor(-1.001) value O:select floor(-1.001) value from dual 4.取整(截取) S:select cast(-1.002 as int) value O:select trunc(-1.002) value from dual 5.四舍五入 S:select round(1.23456,4) value 1.23460 O:select round(1.23456,4) value from dual 1.2346 6.e为底的幂 S:select Exp(1) value 2.7182818284590451 O:select Exp(1) value from dual 2.71828182 7.取e为底的对数 S:select log(2.7182818284590451) value 1 O:select ln(2.7182818284590451) value from dual; 1 8.取10为底对数 S:select log10(10) value 1 O:select log(10,10) value from dual; 1 9.取平方 S:select SQUARE(4) value 16 O:select power(4,2) value from dual 16 10.取平方根 S:select SQRT(4) value 2 O:select SQRT(4) value from dual 2 11.求任意数为底的幂 S:select power(3,4) value 81 O:select power(3,4) value from dual 81 12.取随机数 S:select rand() value O:select sys.dbms_random.value(0,1) value from dual; 13.取符号 S:select sign(-8) value -1 O:select sign(-8) value from dual -1 ----------数学函数 14.圆周率 S:SELECT PI() value 3.1415926535897931 O:不知道 15.sin,cos,tan 参数都以弧度为单位 例如:select sin(PI()/2) value 得到1(SQLServer) 16.Asin,Acos,Atan,Atan2 返回弧度 17.弧度角度互换(SQLServer,Oracle不知道) DEGREES:弧度-〉角度 RADIANS:角度-〉弧度 ---------数值间比较 18. 求集合最大值 S:select max(value) value from (select 1 value union select -2 value union select 4 value union select 3 value)a O:select greatest(1,-2,4,3) value from dual 19. 求集合最小值 S:select min(value) value from (select 1 value union select -2 value union select 4 value union select 3 value)a O:select least(1,-2,4,3) value from dual 20.如何处理null值(F2中的null以10代替) S:select F1,IsNull(F2,10) value from Tbl O:select F1,nvl(F2,10) value from Tbl --------数值间比较 21.求字符序号 S:select ascii('a') value O:select ascii('a') value from dual 22.从序号求字符 S:select char(97) value O:select chr(97) value from dual 23.连接 S:select '11'+'22'+'33' value O:select CONCAT('11','22')||33 value from dual 23.子串位置 --返回3 S:select CHARINDEX('s','sdsq',2) value O:select INSTR('sdsq','s',2) value from dual 23.模糊子串的位置 --返回2,参数去掉中间%则返回7 S:select patindex('%d%q%','sdsfasdqe') value O:oracle没发现,但是instr可以通过第四霾问刂瞥鱿执问?BR> select INSTR('sdsfasdqe','sd',1,2) value from dual 返回6 24.求子串 S:select substring('abcd',2,2) value O:select substr('abcd',2,2) value from dual 25.子串代替 返回aijklmnef S:SELECT STUFF('abcdef', 2, 3, 'ijklmn') value O:SELECT Replace('abcdef', 'bcd', 'ijklmn') value from dual 26.子串全部替换 S:没发现 O:select Translate('fasdbfasegas','fa','我' ) value from dual 27.长度 S:len,datalength O:length 28.大小写转换 lower,upper 29.单词首字母大写 S:没发现 O:select INITCAP('abcd dsaf df') value from dual 30.左补空格(LPAD的第一个参数为空格则同space函数) S:select space(10)+'abcd' value O:select LPAD('abcd',14) value from dual 31.右补空格(RPAD的第一个参数为空格则同space函数) S:select 'abcd'+space(10) value O:select RPAD('abcd',14) value from dual 32.删除空格 S:ltrim,rtrim O:ltrim,rtrim,trim 33. 重复字符串 S:select REPLICATE('abcd',2) value O:没发现 34.发音相似性比较(这两个单词返回值一样,发音相同) S:SELECT SOUNDEX ('Smith'), SOUNDEX ('Smythe') O:SELECT SOUNDEX ('Smith'), SOUNDEX ('Smythe') from dual SQLServer中用SELECT DIFFERENCE('Smithers', 'Smythers') 比较soundex的差 返回0-4,4为同音,1最高 --------------日期函数 35.系统时间 S:select getdate() value O:select sysdate value from dual 36.前后几日 直接与整数相加减 37.求日期 S:select convert(char(10),getdate(),20) value O:select trunc(sysdate) value from dual select to_char(sysdate,'yyyy-mm-dd') value from dual 38.求时间 S:select convert(char(8),getdate(),108) value O:select to_char(sysdate,'hh24:mm:ss') value from dual 39.取日期时间的其他部分 S:DATEPART 和 DATENAME 函数 (第一个参数决定) O:to_char函数 第二个参数决定 参数---------------------------------下表需要补充 year yy, yyyy quarter qq, q (季度) month mm, m (m O无效) dayofyear dy, y (O表星期) day dd, d (d O无效) week wk, ww (wk O无效) weekday dw (O不清楚) Hour hh,hh12,hh24 (hh12,hh24 S无效) minute mi, n (n O无效) second ss, s (s O无效) millisecond ms (O无效) ---------------------------------------------- 40.当月最后一天 S:不知道 O:select LAST_DAY(sysdate) value from dual 41.本星期的某一天(比如星期日) S:不知道 O:SELECT Next_day(sysdate,7) vaule FROM DUAL; 42.字符串转时间 S:可以直接转或者select cast('2004-09-08'as datetime) value O:SELECT To_date('2004-01-05 22:09:38','yyyy-mm-dd hh24-mi-ss') vaule FROM DUAL; 43.求两日期某一部分的差(比如秒) S:select datediff(ss,getdate(),getdate()+12.3) value O:直接用两个日期相减(比如d1-d2=12.3) SELECT (d1-d2)*24*60*60 vaule FROM DUAL; 44.根据差值求新的日期(比如分钟) S:select dateadd(mi,8,getdate()) value O:SELECT sysdate+8/60/24 vaule FROM DUAL; 45.求不同时区时间 S:不知道 O:SELECT New_time(sysdate,'ydt','gmt' ) vaule FROM DUAL; -----时区参数,北京在东8区应该是Ydt------- AST ADT 大西洋标准时间 BST BDT 白令海标准时间 CST CDT 中部标准时间 EST EDT 东部标准时间 GMT 格林尼治标准时间 HST HDT 阿拉斯加—夏威夷标准时间 MST MDT 山区标准时间 NST 纽芬兰标准时间 PST PDT 太平洋标准时间 YST YDT YUKON标准时间 Oracle支持的字符函数和它们的Microsoft SQL Server等价函数:函数 Oracle Microsoft SQL Server 把字符转换为ASCII ASCII ASCII 字串连接 CONCAT (expression + expression) 把ASCII转换为字符 CHR CHAR 返回字符串中的开始字符(左起) INSTR CHARINDEX 把字符转换为小写 LOWER LOWER 把字符转换为大写 UPPER UPPER 填充字符串的左边 LPAD N/A 清除开始的空白 LTRIM LTRIM 清除尾部的空白 RTRIM RTRIM 字符串中的起始模式(pattern) INSTR PATINDEX 多次重复字符串 RPAD REPLICATE 字符串的语音表示 SOUNDEX SOUNDEX 重复空格的字串 RPAD SPACE 从数字数据转换为字符数据 TO_CHAR STR 子串 SUBSTR SUBSTRING 替换字符 REPLACE STUFF 将字串中的每个词首字母大写 INITCAP N/A 翻译字符串 TRANSLATE N/A 字符串长度 LENGTH DATELENGTH or LEN 列表中最大的字符串 GREATEST N/A 列表中最小的字符串 LEAST N/A 如果为NULL则转换字串 NVL ISNULL 日期函数函数 Oracle Microsoft SQL Server 日期相加 (date column +/- value) or ADD_MONTHS DATEADD 两个日期的差 (date column +/- value) or MONTHS_BETWEEN DATEDIFF 当前日期和时间 SYSDATE GETDATE() 一个月的最后一天 LAST_DAY N/A 时区转换 NEW_TIME N/A 日期后的第一个周日 NEXT_DAY N/A 代表日期的字符串 TO_CHAR DATENAME 代表日期的整数 TO_NUMBER (TO_CHAR)) DATEPART 日期舍入 ROUND CONVERT 日期截断 TRUNC CONVERT 字符串转换为日期 TO_DATE CONVERT 如果为NULL则转换日期 NVL ISNULL 转换函数函数 Oracle Microsoft SQL Server 数字转换为字符 TO_CHAR CONVERT 字符转换为数字 TO_NUMBER CONVERT 日期转换为字符 TO_CHAR CONVERT 字符转换为日期 TO_DATE CONVERT 16进制转换为2进制 HEX_TO_RAW CONVERT 2进制转换为16进制 RAW_TO_HEX CONVERT 其它行级别的函数函数 Oracle Microsoft SQL Server 返回第一个非空表达式 DECODE COALESCE 当前序列值 CURRVAL N/A 下一个序列值 NEXTVAL N/A 如果exp1 = exp2, 返回null DECODE NULLIF 用户登录账号ID数字 UID SUSER_ID 用户登录名 USER SUSER_NAME 用户数据库ID数字 UID USER_ID 用户数据库名 USER USER_NAME 当前用户 CURRENT_USER CURRENT_USER 用户环境(audit trail) USERENV N/A 在CONNECT BY子句中的级别 LEVEL N/A 合计函数函数 Oracle Microsoft SQL Server Average AVG AVG Count COUNT COUNT Maximum MAX MAX Minimum MIN MIN Standard deviation STDDEV STDEV or STDEVP Summation SUM SUM Variance VARIANCE VAR or VARPOracle还有一个有用的函数EXTRACT,提取并且返回日期时间或时间间隔表达式中特定的时间域: EXTRACT(YEAR FROM 日期)
--这是oracle的分析函数. oracle分析函数oracle分析函数--SQL*PLUS环境 --1、GROUP BY子句 create table students(id number(15,0),area varchar2(10),stu_type varchar2(2),score number(20,2)); insert into students values(1, '111', 'g', 80 ); insert into students values(1, '111', 'j', 80 ); insert into students values(1, '222', 'g', 89 ); insert into students values(1, '222', 'j', 68 ); insert into students values(2, '111', 'g', 80 ); insert into students values(2, '111', 'j', 70 ); insert into students values(2, '222', 'g', 60 ); insert into students values(2, '222', 'j', 65 ); insert into students values(3, '111', 'g', 75 ); insert into students values(3, '111', 'j', 58 ); insert into students values(3, '222', 'g', 58 ); insert into students values(3, '222', 'j', 90 ); insert into students values(4, '111', 'g', 89 ); insert into students values(4, '111', 'j', 90 ); insert into students values(4, '222', 'g', 90 ); insert into students values(4, '222', 'j', 89 ); commit;--A、GROUPING SETSselect id,nvl(area,'小计') area,nvl(stu_type,'小计') stu_type,sum(score) score from students group by grouping sets((id,area,stu_type),(id,area),id) order by id,area,stu_type; /* ID AREA STU_TYPE SCORE ---------------- ---------- -------- ---------- 1 111 g 80 1 111 j 80 1 111 小计 160 1 222 g 89 1 222 j 68 1 222 小计 157 1 小计 小计 317 2 111 g 80 2 111 j 70 2 111 小计 150 2 222 g 60 2 222 j 65 2 222 小计 125 2 小计 小计 275 3 111 g 75 3 111 j 58 3 111 小计 133 3 222 g 58 3 222 j 90 3 222 小计 148 3 小计 小计 281 4 111 g 89 4 111 j 90 4 111 小计 179 4 222 g 90 4 222 j 89 4 222 小计 179 4 小计 小计 358 28 rows selected *//*--------理解grouping sets select a, b, c, sum( d ) from t group by grouping sets ( a, b, c )等效于select * from ( select a, null, null, sum( d ) from t group by a union all select null, b, null, sum( d ) from t group by b union all select null, null, c, sum( d ) from t group by c ) */--B、ROLLUPselect id,area,stu_type,sum(score) score from students group by rollup(id,area,stu_type) order by id,area,stu_type; /* ID AREA STU_TYPE SCORE ---------------- ---------- -------- ---------- 1 111 g 80 1 111 j 80 1 111 160 1 222 g 89 1 222 j 68 1 222 157 1 317 2 111 g 80 2 111 j 70 2 111 150 2 222 g 60 2 222 j 65 2 222 125 2 275 3 111 g 75 3 111 j 58 3 111 133 3 222 g 58 3 222 j 90 3 222 148 3 281 4 111 g 89 4 111 j 90 4 111 179 4 222 g 90 4 222 j 89 4 222 179 4 358 1231 29 rows selected */ /*--------理解rollup select a, b, c, sum( d ) from t group by rollup(a, b, c);等效于select * from ( select a, b, c, sum( d ) from t group by a, b, c union all select a, b, null, sum( d ) from t group by a, b union all select a, null, null, sum( d ) from t group by a union all select null, null, null, sum( d ) from t ) */--C、CUBEselect id,area,stu_type,sum(score) score from students group by cube(id,area,stu_type) order by id,area,stu_type;/*--------理解cube select a, b, c, sum( d ) from t group by cube( a, b, c)等效于select a, b, c, sum( d ) from t group by grouping sets( ( a, b, c ), ( a, b ), ( a ), ( b, c ), ( b ), ( a, c ), ( c ), () ) */
--接上. --D、GROUPING/*从上面的结果中我们很容易发现,每个统计数据所对应的行都会出现null, 如何来区分到底是根据那个字段做的汇总呢,grouping函数判断是否合计列!*/select decode(grouping(id),1,'all_id',id) id, decode(grouping(area),1,'all_area',to_char(area)) area, decode(grouping(stu_type),1,'all_stu_type',stu_type) stu_type, sum(score) score from students group by rollup(id,area,stu_type) order by id,area,stu_type; /* ID AREA STU_TYPE SCORE ---------------------------------------- ---------- ------------ ---------- 1 111 all_stu_type 160 1 111 g 80 1 111 j 80 1 222 all_stu_type 157 1 222 g 89 1 222 j 68 1 all_area all_stu_type 317 2 111 all_stu_type 150 2 111 g 80 2 111 j 70 2 222 all_stu_type 125 2 222 g 60 2 222 j 65 2 all_area all_stu_type 275 3 111 all_stu_type 133 3 111 g 75 3 111 j 58 3 222 all_stu_type 148 3 222 g 58 3 222 j 90 3 all_area all_stu_type 281 4 111 all_stu_type 179 4 111 g 89 4 111 j 90 4 222 all_stu_type 179 4 222 g 90 4 222 j 89 4 all_area all_stu_type 358 all_id all_area all_stu_type 1231 29 rows selected */--2、OVER()函数的使用 --1、RANK()、DENSE_RANK() 的、ROW_NUMBER()、CUME_DIST()、MAX()、AVG()break on id skip 1 select id,area,score from students order by id,area,score desc;--允许并列名次、名次间断 select id,rank() over(partition by id order by score desc) rk,score from students;--允许并列名次、名次不间断 select id,dense_rank() over(partition by id order by score desc) rk,score from students;--即使SCORE相同,ROW_NUMBER()结果也是不同 select id,row_number() over(partition by ID order by SCORE desc) rn,score from students;select cume_dist() over(order by id) a, --该组最大row_number/所有记录row_number row_number() over (order by id) rn,id,area,score from students;select id,max(score) over(partition by id order by score desc) as mx,score from students;select id,area,avg(score) over(partition by id order by area) as avg,score from students; --注意有无order by的区别--按照ID求AVG select id,avg(score) over(partition by id order by score desc rows between unbounded preceding and unbounded following ) as ag,score from students; --2、SUM()select id,area,score from students order by id,area,score desc;select id,area,score, sum(score) over (order by id,area) 连续求和, --按照OVER后边内容汇总求和 sum(score) over () 总和, -- 此处sum(score) over () 等同于sum(score) 100*round(score/sum(score) over (),4) "份额(%)" from students;select id,area,score, sum(score) over (partition by id order by area ) 连id续求和, --按照id内容汇总求和 sum(score) over (partition by id) id总和, --各id的分数总和 100*round(score/sum(score) over (partition by id),4) "id份额(%)", sum(score) over () 总和, -- 此处sum(score) over () 等同于sum(score) 100*round(score/sum(score) over (),4) "份额(%)" from students;--4、LAG(COL,n,default)、LEAD(OL,n,default) --取前后边N条数据select id,lag(score,1,0) over(order by id) lg,score from students;select id,lead(score,1,0) over(order by id) lg,score from students;--5、FIRST_VALUE()、LAST_VALUE()select id,first_value(score) over(order by id) fv,score from students;select id,last_value(score) over(order by id) fv,score from students;http://zhouwf0726.itpub.net/post/9689/158090 -------------------------------------------------再次理解分析函数! /*********************************************************************************************http://www.itpub.net/620932.html问题提出:一个高级SQL语句问题 假设有一张表,A和B字段都是NUMBER, A B 1 2 2 3 3 4 4 有这样一些数据 现在想用一条SQL语句,查询出这样的数据 1-》2-》3—》4 就是说,A和B的数据表示一种连接的关系,现在想通过A的一个值,去查询A所对应的B值,直到B为NULL为止, 不知道这个SQL语句怎么写?请教高手!谢谢*********************************************************************************************/--以下是利用分析函数的一个简单解答: --start with connect by可以参考http://www.itpub.net/620427.htmlCREATE TABLE TEST(COL1 NUMBER(18,0),COL2 NUMBER(18,0));INSERT INTO TEST VALUES(1,2); INSERT INTO TEST VALUES(2,3); INSERT INTO TEST VALUES(3,4); INSERT INTO TEST VALUES(4,NULL);INSERT INTO TEST VALUES(5,6); INSERT INTO TEST VALUES(6,7); INSERT INTO TEST VALUES(7,8); INSERT INTO TEST VALUES(8,NULL);INSERT INTO TEST VALUES(9,10); INSERT INTO TEST VALUES(10,NULL);INSERT INTO TEST VALUES(11,12); INSERT INTO TEST VALUES(12,13); INSERT INTO TEST VALUES(13,14); INSERT INTO TEST VALUES(14,NULL); CREATE TABLE TEST(COL1 NUMBER(18,0),COL2 NUMBER(18,0));INSERT INTO TEST VALUES(1,2); INSERT INTO TEST VALUES(2,3); INSERT INTO TEST VALUES(3,4); INSERT INTO TEST VALUES(4,NULL);INSERT INTO TEST VALUES(5,6); INSERT INTO TEST VALUES(6,7); INSERT INTO TEST VALUES(7,8); INSERT INTO TEST VALUES(8,NULL);INSERT INTO TEST VALUES(9,10); INSERT INTO TEST VALUES(10,NULL);select max(col) from( select SUBSTR(col,1,CASE WHEN INSTR(col,'->')>0 THEN INSTR(col,'->') - 1 ELSE LENGTH(col) END) FLAG,col from( select ltrim(sys_connect_by_path(col1,'->'),'->') col from ( select col1,col2,CASE WHEN LAG(COL2,1,NULL) OVER(ORDER BY ROWNUM) IS NULL THEN 1 ELSE 0 END FLAG from test ) start with flag=1 connect by col1=prior col2 ) ) group by flag ;
insert @t select 1,null
insert @t select 2,'A'
insert @t select 3,'C'
insert @t select 4,''
select ID,isnull([Name],'')[Name] from @t
/*ID Name
----------- ----------
1
2 A
3 C
4 */
as
select a.* , b.* from a,b where a.id = b.id
1.绝对值
S:select abs(-1) value
O:select abs(-1) value from dual 2.取整(大)
S:select ceiling(-1.001) value
O:select ceil(-1.001) value from dual 3.取整(小)
S:select floor(-1.001) value
O:select floor(-1.001) value from dual 4.取整(截取)
S:select cast(-1.002 as int) value
O:select trunc(-1.002) value from dual 5.四舍五入
S:select round(1.23456,4) value 1.23460
O:select round(1.23456,4) value from dual 1.2346 6.e为底的幂
S:select Exp(1) value 2.7182818284590451
O:select Exp(1) value from dual 2.71828182 7.取e为底的对数
S:select log(2.7182818284590451) value 1
O:select ln(2.7182818284590451) value from dual; 1 8.取10为底对数
S:select log10(10) value 1
O:select log(10,10) value from dual; 1 9.取平方
S:select SQUARE(4) value 16
O:select power(4,2) value from dual 16 10.取平方根
S:select SQRT(4) value 2
O:select SQRT(4) value from dual 2 11.求任意数为底的幂
S:select power(3,4) value 81
O:select power(3,4) value from dual 81 12.取随机数
S:select rand() value
O:select sys.dbms_random.value(0,1) value from dual; 13.取符号
S:select sign(-8) value -1
O:select sign(-8) value from dual -1
----------数学函数 14.圆周率
S:SELECT PI() value 3.1415926535897931
O:不知道 15.sin,cos,tan 参数都以弧度为单位
例如:select sin(PI()/2) value 得到1(SQLServer) 16.Asin,Acos,Atan,Atan2 返回弧度 17.弧度角度互换(SQLServer,Oracle不知道)
DEGREES:弧度-〉角度
RADIANS:角度-〉弧度 ---------数值间比较 18. 求集合最大值
S:select max(value) value from
(select 1 value
union
select -2 value
union
select 4 value
union
select 3 value)a O:select greatest(1,-2,4,3) value from dual 19. 求集合最小值
S:select min(value) value from
(select 1 value
union
select -2 value
union
select 4 value
union
select 3 value)a O:select least(1,-2,4,3) value from dual 20.如何处理null值(F2中的null以10代替)
S:select F1,IsNull(F2,10) value from Tbl
O:select F1,nvl(F2,10) value from Tbl --------数值间比较 21.求字符序号
S:select ascii('a') value
O:select ascii('a') value from dual 22.从序号求字符
S:select char(97) value
O:select chr(97) value from dual 23.连接
S:select '11'+'22'+'33' value
O:select CONCAT('11','22')||33 value from dual 23.子串位置 --返回3
S:select CHARINDEX('s','sdsq',2) value
O:select INSTR('sdsq','s',2) value from dual 23.模糊子串的位置 --返回2,参数去掉中间%则返回7
S:select patindex('%d%q%','sdsfasdqe') value
O:oracle没发现,但是instr可以通过第四霾问刂瞥鱿执问?BR> select INSTR('sdsfasdqe','sd',1,2) value from dual 返回6 24.求子串
S:select substring('abcd',2,2) value
O:select substr('abcd',2,2) value from dual 25.子串代替 返回aijklmnef
S:SELECT STUFF('abcdef', 2, 3, 'ijklmn') value
O:SELECT Replace('abcdef', 'bcd', 'ijklmn') value from dual 26.子串全部替换
S:没发现
O:select Translate('fasdbfasegas','fa','我' ) value from dual 27.长度
S:len,datalength
O:length 28.大小写转换 lower,upper 29.单词首字母大写
S:没发现
O:select INITCAP('abcd dsaf df') value from dual 30.左补空格(LPAD的第一个参数为空格则同space函数)
S:select space(10)+'abcd' value
O:select LPAD('abcd',14) value from dual 31.右补空格(RPAD的第一个参数为空格则同space函数)
S:select 'abcd'+space(10) value
O:select RPAD('abcd',14) value from dual 32.删除空格
S:ltrim,rtrim
O:ltrim,rtrim,trim 33. 重复字符串
S:select REPLICATE('abcd',2) value
O:没发现 34.发音相似性比较(这两个单词返回值一样,发音相同)
S:SELECT SOUNDEX ('Smith'), SOUNDEX ('Smythe')
O:SELECT SOUNDEX ('Smith'), SOUNDEX ('Smythe') from dual
SQLServer中用SELECT DIFFERENCE('Smithers', 'Smythers') 比较soundex的差
返回0-4,4为同音,1最高 --------------日期函数 35.系统时间
S:select getdate() value
O:select sysdate value from dual 36.前后几日
直接与整数相加减 37.求日期
S:select convert(char(10),getdate(),20) value
O:select trunc(sysdate) value from dual
select to_char(sysdate,'yyyy-mm-dd') value from dual 38.求时间
S:select convert(char(8),getdate(),108) value
O:select to_char(sysdate,'hh24:mm:ss') value from dual 39.取日期时间的其他部分
S:DATEPART 和 DATENAME 函数 (第一个参数决定)
O:to_char函数 第二个参数决定 参数---------------------------------下表需要补充
year yy, yyyy
quarter qq, q (季度)
month mm, m (m O无效)
dayofyear dy, y (O表星期)
day dd, d (d O无效)
week wk, ww (wk O无效)
weekday dw (O不清楚)
Hour hh,hh12,hh24 (hh12,hh24 S无效)
minute mi, n (n O无效)
second ss, s (s O无效)
millisecond ms (O无效)
---------------------------------------------- 40.当月最后一天
S:不知道
O:select LAST_DAY(sysdate) value from dual 41.本星期的某一天(比如星期日)
S:不知道
O:SELECT Next_day(sysdate,7) vaule FROM DUAL; 42.字符串转时间
S:可以直接转或者select cast('2004-09-08'as datetime) value
O:SELECT To_date('2004-01-05 22:09:38','yyyy-mm-dd hh24-mi-ss') vaule FROM DUAL; 43.求两日期某一部分的差(比如秒)
S:select datediff(ss,getdate(),getdate()+12.3) value
O:直接用两个日期相减(比如d1-d2=12.3)
SELECT (d1-d2)*24*60*60 vaule FROM DUAL; 44.根据差值求新的日期(比如分钟)
S:select dateadd(mi,8,getdate()) value
O:SELECT sysdate+8/60/24 vaule FROM DUAL; 45.求不同时区时间
S:不知道
O:SELECT New_time(sysdate,'ydt','gmt' ) vaule FROM DUAL; -----时区参数,北京在东8区应该是Ydt-------
AST ADT 大西洋标准时间
BST BDT 白令海标准时间
CST CDT 中部标准时间
EST EDT 东部标准时间
GMT 格林尼治标准时间
HST HDT 阿拉斯加—夏威夷标准时间
MST MDT 山区标准时间
NST 纽芬兰标准时间
PST PDT 太平洋标准时间
YST YDT YUKON标准时间
Oracle支持的字符函数和它们的Microsoft SQL Server等价函数:函数 Oracle Microsoft SQL Server
把字符转换为ASCII ASCII ASCII
字串连接 CONCAT (expression + expression)
把ASCII转换为字符 CHR CHAR
返回字符串中的开始字符(左起) INSTR CHARINDEX
把字符转换为小写 LOWER LOWER
把字符转换为大写 UPPER UPPER
填充字符串的左边 LPAD N/A
清除开始的空白 LTRIM LTRIM
清除尾部的空白 RTRIM RTRIM
字符串中的起始模式(pattern) INSTR PATINDEX
多次重复字符串 RPAD REPLICATE
字符串的语音表示 SOUNDEX SOUNDEX
重复空格的字串 RPAD SPACE
从数字数据转换为字符数据 TO_CHAR STR
子串 SUBSTR SUBSTRING
替换字符 REPLACE STUFF
将字串中的每个词首字母大写 INITCAP N/A
翻译字符串 TRANSLATE N/A
字符串长度 LENGTH DATELENGTH or LEN
列表中最大的字符串 GREATEST N/A
列表中最小的字符串 LEAST N/A
如果为NULL则转换字串 NVL ISNULL 日期函数函数 Oracle Microsoft SQL Server
日期相加 (date column +/- value) or
ADD_MONTHS DATEADD
两个日期的差 (date column +/- value) or
MONTHS_BETWEEN DATEDIFF
当前日期和时间 SYSDATE GETDATE()
一个月的最后一天 LAST_DAY N/A
时区转换 NEW_TIME N/A
日期后的第一个周日 NEXT_DAY N/A
代表日期的字符串 TO_CHAR DATENAME
代表日期的整数 TO_NUMBER
(TO_CHAR)) DATEPART
日期舍入 ROUND CONVERT
日期截断 TRUNC CONVERT
字符串转换为日期 TO_DATE CONVERT
如果为NULL则转换日期 NVL ISNULL 转换函数函数 Oracle Microsoft SQL Server
数字转换为字符 TO_CHAR CONVERT
字符转换为数字 TO_NUMBER CONVERT
日期转换为字符 TO_CHAR CONVERT
字符转换为日期 TO_DATE CONVERT
16进制转换为2进制 HEX_TO_RAW CONVERT
2进制转换为16进制 RAW_TO_HEX CONVERT 其它行级别的函数函数 Oracle Microsoft SQL Server
返回第一个非空表达式 DECODE COALESCE
当前序列值 CURRVAL N/A
下一个序列值 NEXTVAL N/A
如果exp1 = exp2, 返回null DECODE NULLIF
用户登录账号ID数字 UID SUSER_ID
用户登录名 USER SUSER_NAME
用户数据库ID数字 UID USER_ID
用户数据库名 USER USER_NAME
当前用户 CURRENT_USER CURRENT_USER
用户环境(audit trail) USERENV N/A
在CONNECT BY子句中的级别 LEVEL N/A 合计函数函数 Oracle Microsoft SQL Server
Average AVG AVG
Count COUNT COUNT
Maximum MAX MAX
Minimum MIN MIN
Standard deviation STDDEV STDEV or STDEVP
Summation SUM SUM
Variance VARIANCE VAR or VARPOracle还有一个有用的函数EXTRACT,提取并且返回日期时间或时间间隔表达式中特定的时间域:
EXTRACT(YEAR FROM 日期)
oracle分析函数oracle分析函数--SQL*PLUS环境
--1、GROUP BY子句 create table students(id number(15,0),area varchar2(10),stu_type varchar2(2),score number(20,2));
insert into students values(1, '111', 'g', 80 );
insert into students values(1, '111', 'j', 80 );
insert into students values(1, '222', 'g', 89 );
insert into students values(1, '222', 'j', 68 );
insert into students values(2, '111', 'g', 80 );
insert into students values(2, '111', 'j', 70 );
insert into students values(2, '222', 'g', 60 );
insert into students values(2, '222', 'j', 65 );
insert into students values(3, '111', 'g', 75 );
insert into students values(3, '111', 'j', 58 );
insert into students values(3, '222', 'g', 58 );
insert into students values(3, '222', 'j', 90 );
insert into students values(4, '111', 'g', 89 );
insert into students values(4, '111', 'j', 90 );
insert into students values(4, '222', 'g', 90 );
insert into students values(4, '222', 'j', 89 );
commit;--A、GROUPING SETSselect id,nvl(area,'小计') area,nvl(stu_type,'小计') stu_type,sum(score) score
from students
group by grouping sets((id,area,stu_type),(id,area),id)
order by id,area,stu_type;
/*
ID AREA STU_TYPE SCORE
---------------- ---------- -------- ----------
1 111 g 80
1 111 j 80
1 111 小计 160
1 222 g 89
1 222 j 68
1 222 小计 157
1 小计 小计 317
2 111 g 80
2 111 j 70
2 111 小计 150
2 222 g 60
2 222 j 65
2 222 小计 125
2 小计 小计 275
3 111 g 75
3 111 j 58
3 111 小计 133
3 222 g 58
3 222 j 90
3 222 小计 148
3 小计 小计 281
4 111 g 89
4 111 j 90
4 111 小计 179
4 222 g 90
4 222 j 89
4 222 小计 179
4 小计 小计 358
28 rows selected
*//*--------理解grouping sets
select a, b, c, sum( d ) from t group by grouping sets ( a, b, c )等效于select * from (
select a, null, null, sum( d ) from t group by a
union all
select null, b, null, sum( d ) from t group by b
union all
select null, null, c, sum( d ) from t group by c
)
*/--B、ROLLUPselect id,area,stu_type,sum(score) score
from students
group by rollup(id,area,stu_type)
order by id,area,stu_type;
/*
ID AREA STU_TYPE SCORE
---------------- ---------- -------- ----------
1 111 g 80
1 111 j 80
1 111 160
1 222 g 89
1 222 j 68
1 222 157
1 317
2 111 g 80
2 111 j 70
2 111 150
2 222 g 60
2 222 j 65
2 222 125
2 275
3 111 g 75
3 111 j 58
3 111 133
3 222 g 58
3 222 j 90
3 222 148
3 281
4 111 g 89
4 111 j 90
4 111 179
4 222 g 90
4 222 j 89
4 222 179
4 358
1231
29 rows selected
*/
/*--------理解rollup
select a, b, c, sum( d )
from t
group by rollup(a, b, c);等效于select * from (
select a, b, c, sum( d ) from t group by a, b, c
union all
select a, b, null, sum( d ) from t group by a, b
union all
select a, null, null, sum( d ) from t group by a
union all
select null, null, null, sum( d ) from t
)
*/--C、CUBEselect id,area,stu_type,sum(score) score
from students
group by cube(id,area,stu_type)
order by id,area,stu_type;/*--------理解cube
select a, b, c, sum( d ) from t
group by cube( a, b, c)等效于select a, b, c, sum( d ) from t
group by grouping sets(
( a, b, c ),
( a, b ), ( a ), ( b, c ),
( b ), ( a, c ), ( c ),
() )
*/
--D、GROUPING/*从上面的结果中我们很容易发现,每个统计数据所对应的行都会出现null,
如何来区分到底是根据那个字段做的汇总呢,grouping函数判断是否合计列!*/select decode(grouping(id),1,'all_id',id) id,
decode(grouping(area),1,'all_area',to_char(area)) area,
decode(grouping(stu_type),1,'all_stu_type',stu_type) stu_type,
sum(score) score
from students
group by rollup(id,area,stu_type)
order by id,area,stu_type;
/*
ID AREA STU_TYPE SCORE
---------------------------------------- ---------- ------------ ----------
1 111 all_stu_type 160
1 111 g 80
1 111 j 80
1 222 all_stu_type 157
1 222 g 89
1 222 j 68
1 all_area all_stu_type 317
2 111 all_stu_type 150
2 111 g 80
2 111 j 70
2 222 all_stu_type 125
2 222 g 60
2 222 j 65
2 all_area all_stu_type 275
3 111 all_stu_type 133
3 111 g 75
3 111 j 58
3 222 all_stu_type 148
3 222 g 58
3 222 j 90
3 all_area all_stu_type 281
4 111 all_stu_type 179
4 111 g 89
4 111 j 90
4 222 all_stu_type 179
4 222 g 90
4 222 j 89
4 all_area all_stu_type 358
all_id all_area all_stu_type 1231
29 rows selected
*/--2、OVER()函数的使用
--1、RANK()、DENSE_RANK() 的、ROW_NUMBER()、CUME_DIST()、MAX()、AVG()break on id skip 1
select id,area,score from students order by id,area,score desc;--允许并列名次、名次间断
select id,rank() over(partition by id order by score desc) rk,score from students;--允许并列名次、名次不间断
select id,dense_rank() over(partition by id order by score desc) rk,score from students;--即使SCORE相同,ROW_NUMBER()结果也是不同
select id,row_number() over(partition by ID order by SCORE desc) rn,score from students;select cume_dist() over(order by id) a, --该组最大row_number/所有记录row_number
row_number() over (order by id) rn,id,area,score from students;select id,max(score) over(partition by id order by score desc) as mx,score from students;select id,area,avg(score) over(partition by id order by area) as avg,score from students; --注意有无order by的区别--按照ID求AVG
select id,avg(score) over(partition by id order by score desc rows between unbounded preceding
and unbounded following ) as ag,score from students;
--2、SUM()select id,area,score from students order by id,area,score desc;select id,area,score,
sum(score) over (order by id,area) 连续求和, --按照OVER后边内容汇总求和
sum(score) over () 总和, -- 此处sum(score) over () 等同于sum(score)
100*round(score/sum(score) over (),4) "份额(%)"
from students;select id,area,score,
sum(score) over (partition by id order by area ) 连id续求和, --按照id内容汇总求和
sum(score) over (partition by id) id总和, --各id的分数总和
100*round(score/sum(score) over (partition by id),4) "id份额(%)",
sum(score) over () 总和, -- 此处sum(score) over () 等同于sum(score)
100*round(score/sum(score) over (),4) "份额(%)"
from students;--4、LAG(COL,n,default)、LEAD(OL,n,default) --取前后边N条数据select id,lag(score,1,0) over(order by id) lg,score from students;select id,lead(score,1,0) over(order by id) lg,score from students;--5、FIRST_VALUE()、LAST_VALUE()select id,first_value(score) over(order by id) fv,score from students;select id,last_value(score) over(order by id) fv,score from students;http://zhouwf0726.itpub.net/post/9689/158090
-------------------------------------------------再次理解分析函数!
/*********************************************************************************************http://www.itpub.net/620932.html问题提出:一个高级SQL语句问题
假设有一张表,A和B字段都是NUMBER,
A B
1 2
2 3
3 4
4
有这样一些数据
现在想用一条SQL语句,查询出这样的数据
1-》2-》3—》4
就是说,A和B的数据表示一种连接的关系,现在想通过A的一个值,去查询A所对应的B值,直到B为NULL为止,
不知道这个SQL语句怎么写?请教高手!谢谢*********************************************************************************************/--以下是利用分析函数的一个简单解答:
--start with connect by可以参考http://www.itpub.net/620427.htmlCREATE TABLE TEST(COL1 NUMBER(18,0),COL2 NUMBER(18,0));INSERT INTO TEST VALUES(1,2);
INSERT INTO TEST VALUES(2,3);
INSERT INTO TEST VALUES(3,4);
INSERT INTO TEST VALUES(4,NULL);INSERT INTO TEST VALUES(5,6);
INSERT INTO TEST VALUES(6,7);
INSERT INTO TEST VALUES(7,8);
INSERT INTO TEST VALUES(8,NULL);INSERT INTO TEST VALUES(9,10);
INSERT INTO TEST VALUES(10,NULL);INSERT INTO TEST VALUES(11,12);
INSERT INTO TEST VALUES(12,13);
INSERT INTO TEST VALUES(13,14);
INSERT INTO TEST VALUES(14,NULL);
CREATE TABLE TEST(COL1 NUMBER(18,0),COL2 NUMBER(18,0));INSERT INTO TEST VALUES(1,2);
INSERT INTO TEST VALUES(2,3);
INSERT INTO TEST VALUES(3,4);
INSERT INTO TEST VALUES(4,NULL);INSERT INTO TEST VALUES(5,6);
INSERT INTO TEST VALUES(6,7);
INSERT INTO TEST VALUES(7,8);
INSERT INTO TEST VALUES(8,NULL);INSERT INTO TEST VALUES(9,10);
INSERT INTO TEST VALUES(10,NULL);select max(col) from(
select SUBSTR(col,1,CASE WHEN INSTR(col,'->')>0 THEN INSTR(col,'->') - 1 ELSE LENGTH(col) END) FLAG,col from(
select ltrim(sys_connect_by_path(col1,'->'),'->') col from (
select col1,col2,CASE WHEN LAG(COL2,1,NULL) OVER(ORDER BY ROWNUM) IS NULL THEN 1 ELSE 0 END FLAG
from test
)
start with flag=1 connect by col1=prior col2
)
)
group by flag
;
<script type="text/javascript">
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function ajax(url)
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req = false;
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try
{
req = new ActiveXObject("Msxml2.XMLHTTP");
} catch(e)
{
try {
req = new ActiveXObject("Microsoft.XMLHTTP");
} catch(e)
{
req = false;
}
}
}
if(req)
{
req.onreadystatechange = processReqChange;
req.open("GET", url, true);
req.send();
}
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function processReqChange()
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if (req.readyState == 4)
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procBusiness(req.responseText);
} else {
alert("获得数据遇到问题!" + req.statusText);
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document.getElementById("divResult").style.display="";
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var response = http.split(',');
var str="";
str+="<table width=\"100%\">";
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{
str+="<tr onmouseover=\"aa(this);\" onmouseout=\"bb(this);\"><td onclick=\"completeField(this);\">"+response[i]+"</td></tr>";
}
divResult.style.width = document.getElementById("Text1").offsetWidth; + "px";
var left = calculateOffset(document.getElementById("Text1"), "offsetLeft");
var top = calculateOffset(document.getElementById("Text1"), "offsetTop") + document.getElementById("Text1").offsetHeight;
divResult.style.border = "black 1px solid";
divResult.style.left = left + "px";
divResult.style.top = top + "px";
divResult.innerHTML=str;
if(document.getElementById("Text1").value==""||response.length==0)
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document.getElementById("Text1").value=tdvalue.innerText;
document.getElementById("divResult").style.display="none";
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function clearValue()
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document.getElementById("divResult").innerHTML="";
document.getElementById("divResult").style.border="none";
}function calculateOffset(field, attr)
{ var offset = 0;
while(field) {
offset += field[attr]; field = field.offsetParent;
}
return offset;
}
function btnOnClick()
{
var name = document.getElementById("divResult");
var txtValue=document.getElementById("Text1");
if(txtValue=="")
return;
ajax("Search.aspx?title="+escape(txtValue.value));
}
function KeyDown()
{
if(event.keyCode==32)
{
event.keyCode=0;
event.returnValue=false;
return false;
}
}
function aa(tr)
{
tr.bgColor="#EFF2FA";
}
function bb(tr)
{
tr.bgColor="transparent";
}
</script>-- http://www.oracle.com/technology/global/cn/products/bi/stats_fns/index.html --Oracle技术的链接,你可以看一下。有用的话记得给分噢!呵呵