一尘不染

MySQL GroupBy并水平显示

sql

假设我有下表：

1) tblScore

============================ 
Date      VendorID     Score 
============================ 
12/09/01  12001        A     
12/09/01  12001        A     
12/09/01  12002        B     
12/09/02  12003        C     
12/09/02  12003        A     
12/09/03  12001        C     
============================

我有这个查询：

SELECT ts.VendorID, ts.Score, COUNT(*)
FROM trxscore ts
GROUP BY ts.VendorID, ts.Score
ORDER BY ts.VendorID, ts.Score

但是如何显示该表，如下所示：

===========================
VendorID    A    B    C
===========================
12001       2    0    1
12002       0    1    0 
12003       1    0    1
===========================

而且，是否可以从文本中获取平均值？即，VendorID 12001应该得到A的平均值。谢谢…

阅读 182

2021-05-23

共1个答案

一尘不染

试试这个，

SELECT  VendorID,
        SUM(CASE WHEN Score = 'A' THEN 1 ELSE 0 END) totalA,
        SUM(CASE WHEN Score = 'B' THEN 1 ELSE 0 END) totalB,
        SUM(CASE WHEN Score = 'C' THEN 1 ELSE 0 END) totalC
FROM    tableName
GROUP BY VendorID

SQLFiddle演示

2021-05-23