怎么把这样一个表儿
year month amount
1991 1 1.1
1991 2 1.2
1991 3 1.3
1991 4 1.4
1992 1 2.1
1992 2 2.2
1992 3 2.3
1992 4 2.4
查成这样一个结果
year m1 m2 m3 m4
1991 1.1 1.2 1.3 1.4
1992 2.1 2.2 2.3 2.4
year month amount
1991 1 1.1
1991 2 1.2
1991 3 1.3
1991 4 1.4
1992 1 2.1
1992 2 2.2
1992 3 2.3
1992 4 2.4
查成这样一个结果
year m1 m2 m3 m4
1991 1.1 1.2 1.3 1.4
1992 2.1 2.2 2.3 2.4
YEAR,
SUM(IF(MONTH=1,amount,0)) AS m1,
SUM(IF(MONTH=2,amount,0)) AS m2,
SUM(IF(MONTH=3,amount,0)) AS m3,
SUM(IF(MONTH=4,amount,0)) AS m4
FROM a
GROUP BY YEAR
YEAR,
SUM(CASE MONTH WHEN 1 THEN amount ELSE 0 END) AS m1,
SUM(CASE MONTH WHEN 2 THEN amount ELSE 0 END) AS m2,
SUM(CASE MONTH WHEN 3 THEN amount ELSE 0 END) AS m3,
SUM(CASE MONTH WHEN 4 THEN amount ELSE 0 END) AS m4
FROM a
GROUP BY YEAR
用 case when zhen 的语法也可以,结果一样,这个数据是死的 ,如果数据是动态的就不行了。。
就必须用变量了
sum(if(a.month='2',amount,0)) as 'm2',
sum(if(a.month='3',amount,0)) as 'm3',
sum(if(a.month='4',amount,0)) as 'm4'
from row_column_test a
group by a.year;
CREATE TABLE t1
(
nian INT,
yue INT,
amount DECIMAL(18,1)
)
INSERT INTO t1
SELECT 1991, 1, 1.1 UNION ALL
SELECT 1991, 2, 1.2 UNION ALL
SELECT 1991, 3, 1.3 UNION ALL
SELECT 1991, 4, 1.4 UNION ALL
SELECT 1992, 1, 2.1 UNION ALL
SELECT 1992, 2, 2.2 UNION ALL
SELECT 1992, 3, 2.3 UNION ALL
SELECT 1992, 4, 2.4
SELECT * FROM t1DECLARE @str VARCHAR(8000)
SET @str='select nian'
SELECT @str=@str+',max(case when yue='+LTRIM(yue)+' then amount else 0 end) as ['+LTRIM(yue)+']'
FROM (SELECT DISTINCT yue FROM t1) AS a1
SET @str=@str+' from t1 group by nian'
PRINT @str
EXEC (@str)-----------------
nian 1 2 3 4
1991 1.1 1.2 1.3 1.4
1992 2.1 2.2 2.3 2.4
SET @str='select nian'
SELECT @str=@str+',max(case when yue='+LTRIM(yue)+' then amount else 0 end) as [m'+LTRIM(yue)+']'
FROM (SELECT DISTINCT yue FROM t1) AS a1
SET @str=@str+' from t1 group by nian'
PRINT @str
EXEC (@str)---------------------
nian m1 m2 m3 m4
1991 1.1 1.2 1.3 1.4
1992 2.1 2.2 2.3 2.4