Question

我想从不同的表中选择3列，但我必须使用函数，这是我想要的查询：

SELECT DISTINCT table1.sum(column1) as sumcol1,
      table2.sum(column2) as sumcol2, table3.column3 as col3 
 FROM db1.table1, db1.table2, db1.table3 
WHERE table1.id = 1  AND table2.id = 1 AND table3.id = 1;

注意：只有table3.id是唯一索引
我想得到这张表：

 |sumcol1|sumcol2|col3|
 |1234556|5432113|432|

Answer 1

既然你没有提到逻辑。看起来像missplaced SUM

SELECT DISTINCT sum(table1.column1) as sumcol1,
          sum(table2.column2) as sumcol2, table3.column3 as col3 
     FROM db1.table1, db1.table2, db1.table3 
    WHERE table1.id = 1  AND table2.id = 1 AND table3.id = 1;

Answer 2

我找到了解决方案，很简单。

SELECT DISTINCT sum（table1.column1）为sumcol1，sum（table2.column2）为sumcol2，table3.column3为col3 FROM db1.table1，db1.table2，db1.table3 WHERE table1.id = 1 AND table2.id = 1 AND table3.id = 1;

我只是为sum（table1.column1）更改table1.sum（column1），并为sum更改table2.sum（column2）（table2.column2）

我如何在MySQL中执行此查询（来自不同表的多个列）

2 个答案: