将多行中的数据合并为一行

Question

我在 SQL 中合并（合并）行时遇到困难：我正在寻找包含

的行

CLIENTID，所有级别的总计数，级别计数（在每个级别）。

这是一个例子：

ClientID    Total Counts    Level1  Level2  Level3
1234566     12              9        3      0

这是我拥有的代码，我对它进行了扭曲和转换，但它总是很短：它在每个级别都给我空值，除了那个。但我希望数据全部组合成一行。提前非常感谢你

            SELECT u.clientID AS CLIENTID_SHORT, 
            CASE WHEN LEVEL='1' THEN COUNT(*) END AS Level1,
            CASE WHEN LEVEL='2' THEN COUNT(*) END AS Level2,
            CASE WHEN LEVEL='3' THEN COUNT(*) END AS Level3,
            CASE WHEN LEVEL='4' THEN COUNT(*) END AS Level4,
            CASE WHEN LEVEL='5' THEN COUNT(*) END AS Level5
            FROM CLIENTPROFILE u
            GROUP BY u.ClientID, u.LEVEL
            ORDER BY CLIENTID_SHORT

Answer 1

在case 声明之上应用count

SELECT u.clientID AS CLIENTID_SHORT,
       Count(*) AS TotalLevelCount,
       Count(CASE WHEN LEVEL = 1 THEN 1 END) AS Level1,
       Count(CASE WHEN LEVEL = 2 THEN 1 END) AS Level2,
       Count(CASE WHEN LEVEL = 3 THEN 1 END) AS Level3,
       Count(CASE WHEN LEVEL = 4 THEN 1 END) AS Level4,
       Count(CASE WHEN LEVEL = 5 THEN 1 END) AS Level5
FROM   CLIENTPROFILE u
WHERE  LEVEL >= 1
       AND Level <= 5
GROUP  BY u.ClientID
ORDER  BY CLIENTID_SHORT 

注意：在检查整数列时不必使用单引号。