构造sql语句

Question

查询功能中，如何把查询条件和添加到sql语句里.
什么叫'查询条件和'??

Answer 1

更正：“如何把查询条件和添加到sql语句里”打多了个“和”字。不好意思

Answer 2

那不就是使用动态SQL就行了，
使用字符窜构造，使用动态SQL执行。
动态sql
str:='select colname from '||v_tbname||' where rownum=1';
execute immediate str into v_coldata;

Answer 3

可能是我表达得不够清楚.
具体点就是,我要实现如下函数：
private String addClouse(String strSQL//SQL查询语句,String strWhereClouse//形如"name='小李'"的条件)
{
   
   return "";
}
其中strSQL是一个完整的SQL语句，可能有where条件，order by,group by,嵌套查询，联合查询等。而strWhereClouse是一个形如"name='小李'"的字符串.
如何返回一条合并后合法的SQL语句

Answer 4

要实现的话，还得有更多的规则才行，比如：不能为order by，group by语句，...，然后才可能根据不同情况判断、构造

Answer 5

那不是还是字符串的构造吗？
使用SUBSTR（strSQL，1,INSRT（strSQL，'WHERE'））||'name=''小李'''
你知道字符串的连接就OK了

Answer 6

是是字符串的构造。但要判断该不该加where,该不该加and,加在什么地方。
strSQL可以是简单的如"select * from tablename"
也可以是：
select * from dd_produce_journal,(select dd_pj_no,
max(decode(forecast_time,'01:00',forecast_burden)) forecast_burden1,
max(decode(forecast_time,'01:00',real_burden))real_burden1,
max(decode(forecast_time,'02:00',forecast_burden))forecast_burden2,
max(decode(forecast_time,'02:00',real_burden))real_burden2,
max(decode(forecast_time,'03:00',forecast_burden))forecast_burden3,
max(decode(forecast_time,'03:00',real_burden))real_burden3,
max(decode(forecast_time,'04:00',forecast_burden)) forecast_burden4,
max(decode(forecast_time,'04:00',real_burden))real_burden4,
max(decode(forecast_time,'05:00',forecast_burden))forecast_burden5,
max(decode(forecast_time,'05:00',real_burden))real_burden5,
max(decode(forecast_time,'06:00',forecast_burden))forecast_burden6,
max(decode(forecast_time,'06:00',real_burden))real_burden6,
max(decode(forecast_time,'07:00',forecast_burden))forecast_burden7,
max(decode(forecast_time,'07:00',real_burden))real_burden7,
max(decode(forecast_time,'08:00',forecast_burden))forecast_burden8,
max(decode(forecast_time,'08:00',real_burden))real_burden8,
max(decode(forecast_time,'09:00',forecast_burden))forecast_burden9,
max(decode(forecast_time,'09:00',real_burden))real_burden9,
max(decode(forecast_time,'10:00',forecast_burden))forecast_burden10,
max(decode(forecast_time,'10:00',real_burden))real_burden10,
max(decode(forecast_time,'11:00',forecast_burden))forecast_burden11,
max(decode(forecast_time,'11:00',real_burden))real_burden11,
max(decode(forecast_time,'12:00',forecast_burden))forecast_burden12,
max(decode(forecast_time,'12:00',real_burden))real_burden12,
max(decode(forecast_time,'13:00',forecast_burden))forecast_burden13,
max(decode(forecast_time,'13:00',real_burden)) real_burden13,
max(decode(forecast_time,'14:00',forecast_burden))forecast_burden14,
max(decode(forecast_time,'14:00',real_burden))real_burden14,
max(decode(forecast_time,'15:00',forecast_burden))forecast_burden15,
max(decode(forecast_time,'15:00',real_burden))real_burden15,
max(decode(forecast_time,'16:00',forecast_burden))forecast_burden16,
max(decode(forecast_time,'16:00',real_burden))real_burden16,
max(decode(forecast_time,'17:00',forecast_burden))forecast_burden17,
max(decode(forecast_time,'17:00',real_burden))real_burden17,
max(decode(forecast_time,'18:00',forecast_burden))forecast_burden18,
max(decode(forecast_time,'18:00',real_burden))real_burden18,
max(decode(forecast_time,'19:00',forecast_burden))forecast_burden19,
max(decode(forecast_time,'19:00',real_burden))real_burden19,
max(decode(forecast_time,'20:00',forecast_burden))forecast_burden20,
max(decode(forecast_time,'20:00',real_burden))real_burden20,
max(decode(forecast_time,'21:00',forecast_burden))forecast_burden21,
max(decode(forecast_time,'21:00',real_burden))real_burden21,
max(decode(forecast_time,'22:00',forecast_burden))forecast_burden22,
max(decode(forecast_time,'22:00',real_burden))real_burden22,
max(decode(forecast_time,'23:00',forecast_burden))forecast_burden23,
max(decode(forecast_time,'23:00',real_burden))real_burden23,
max(decode(forecast_time,'24:00',forecast_burden))forecast_burden24,
max(decode(forecast_time,'24:00',real_burden))real_burden24 from dd_dd_forecast_dayreport group by dd_pj_no)b
where dd_produce_journal.dd_pj_no=b.dd_pj_no
或者：select t1.dd_rm_date,t1.station_name as station_name_l,t1.line_name as line_name_l,t1.dd_rm_runstate_morning as dd_rm_runstate_morning_l,t1.dd_rm_runstate_noon as dd_rm_runstate_noon_l,t1.dd_rm_runstate_night as dd_rm_runstate_night_l,t2.station_name as station_name_r,t2.line_name as line_name_r,t2.dd_rm_runstate_morning as dd_rm_runstate_morning_r,t2.dd_rm_runstate_noon as dd_rm_runstate_noon_r,t2.dd_rm_runstate_night as dd_rm_runstate_night_r from (select * from (select (select count(*)+1 from 
(select a.dd_rm_id,a.DD_RM_DATE,a.TRANSFORMERSUBSTATIONID as station_name,a.DD_RM_ROUTENAME as line_name,a.DD_RM_RUNSTATE as dd_rm_runstate_morning,b.DD_RM_RUNSTATE as dd_rm_runstate_noon,c.DD_RM_RUNSTATE as dd_rm_runstate_night from dd_running_mode a,dd_running_mode b,dd_running_mode c where a.transformersubstationid=b.transformersubstationid and b.transformersubstationid=c.transformersubstationid and a.dd_rm_routename=b.dd_rm_routename and b.dd_rm_routename=c.dd_rm_routename and a.dd_rm_date=b.dd_rm_date and b.dd_rm_date=c.dd_rm_date and a.dd_rm_classmode='白班' and b.dd_rm_classmode='中班' and c.dd_rm_classmode='夜班') tem_tbl1 where 
tem_tbl1.dd_rm_id<a.dd_rm_id) as rec_no,a.*  from 
(select a.dd_rm_id,a.DD_RM_DATE,a.TRANSFORMERSUBSTATIONID as station_name,a.DD_RM_ROUTENAME as line_name,a.DD_RM_RUNSTATE as dd_rm_runstate_morning,b.DD_RM_RUNSTATE as dd_rm_runstate_noon,c.DD_RM_RUNSTATE as dd_rm_runstate_night from dd_running_mode a,dd_running_mode b,dd_running_mode c where a.transformersubstationid=b.transformersubstationid and b.transformersubstationid=c.transformersubstationid and a.dd_rm_routename=b.dd_rm_routename and b.dd_rm_routename=c.dd_rm_routename and a.dd_rm_date=b.dd_rm_date and b.dd_rm_date=c.dd_rm_date and a.dd_rm_classmode='白班' and b.dd_rm_classmode='中班' and c.dd_rm_classmode='夜班') a) b where 
mod(b.rec_no,2)=1) t1 left outer join (select * from (select (select count(*)+1 from 
(select a.dd_rm_id,a.DD_RM_DATE,a.TRANSFORMERSUBSTATIONID as station_name,a.DD_RM_ROUTENAME as line_name,a.DD_RM_RUNSTATE as dd_rm_runstate_morning,b.DD_RM_RUNSTATE as dd_rm_runstate_noon,c.DD_RM_RUNSTATE as dd_rm_runstate_night from dd_running_mode a,dd_running_mode b,dd_running_mode c where a.transformersubstationid=b.transformersubstationid and b.transformersubstationid=c.transformersubstationid and a.dd_rm_routename=b.dd_rm_routename and b.dd_rm_routename=c.dd_rm_routename and a.dd_rm_date=b.dd_rm_date and b.dd_rm_date=c.dd_rm_date and a.dd_rm_classmode='白班' and b.dd_rm_classmode='中班' and c.dd_rm_classmode='夜班') tem_tbl2 where 
tem_tbl2.dd_rm_id<a.dd_rm_id) as rec_no,a.*  from 
(select a.dd_rm_id,a.DD_RM_DATE,a.TRANSFORMERSUBSTATIONID as station_name,a.DD_RM_ROUTENAME as line_name,a.DD_RM_RUNSTATE as dd_rm_runstate_morning,b.DD_RM_RUNSTATE as dd_rm_runstate_noon,c.DD_RM_RUNSTATE as dd_rm_runstate_night from dd_running_mode a,dd_running_mode b,dd_running_mode c where a.transformersubstationid=b.transformersubstationid and b.transformersubstationid=c.transformersubstationid and a.dd_rm_routename=b.dd_rm_routename and b.dd_rm_routename=c.dd_rm_routename and a.dd_rm_date=b.dd_rm_date and b.dd_rm_date=c.dd_rm_date and a.dd_rm_classmode='白班' and b.dd_rm_classmode='中班' and c.dd_rm_classmode='夜班') a) b where 
mod(b.rec_no,2)=0) t2 on t2.rec_no-t1.rec_no=1 order by t1.rec_no

Answer 7

可以实把整条语句写出来，是这样
select * from table where nvl2(value,字段,1)=nvl(value,1) group by value order by valuegoup by value --假如value是空，不受任何影响