Question

我是sql查询的初学者，我想问一个问题。

我有2个表，即dbo.Group_Master和dbo.Group_Assign。

     TABLE : GROUP MASTER

| GROUP_ID      |    GROUP_DESC     |
|------------   |:---------------:  |
| PMD           |   POWER MOTOR     |
| ASSY          |     ASSEMBLY      |
| FINANCE       |   FINANCE DEPT    |
| COSTING       | COSTING DEPT      |
| IE            | IMPORT EXPORT     |
| BBC GROUP     | BBC GROUP         |
| PRODUCTION    | PRODUCTION DEPT   |
| PURCHASING    | PURCHASING        |
| SALE          | SALE DEPT         |
| MMASTER       | MATERIAL MASTER   |


          TABLE : GROUP_ASSIGN

| JOB_ID    | STEP_ID   | LOG_NAME  | GROUP_ID  |
|--------   |:-------:  |---------- |---------- |
| J1        |    1      | ACCOUNT   | PMD       |
| J1        |    2      | ACCOUNT   | ASSY      |
| J1        |    3      | ACCOUNT   | SALE      |
| J1        |    1      | FREIGHT   | IE        |

当我加入两个表并放入where子句时，运行如下的查询

SELECT
   a.GROUP_ID,
   a.GROUP_DESC, 
   CASE WHEN b.GROUP_ID IS NULL THEN '0' ELSE '1' end as status 
FROM dbo.GROUP_MASTER A 
LEFT JOIN dbo.GROUP_ASSIGN B ON (B.GROUP_ID = a.GROUP_ID)
WHERE B.LOG_NAME LIKE 'ACCOUNT'

playsound

我想要的是结果管理显示所有前2列，只有第3列受where子句影响，如下图所示。我有什么方法可以做到吗？

It display result like this :

Answer 1

尝试以下查询...

SELECT
   A.GROUP_ID,
   A.GROUP_DESC, 
   CASE WHEN B.GROUP_ID IS NULL THEN '0' ELSE '1' end as status 
FROM dbo.GROUP_MASTER A 
LEFT JOIN (SELECT * FROM dbo.GROUP_ASSIGN WHERE LOG_NAME LIKE 'ACCOUNT') B ON (A.GROUP_ID = B.GROUP_ID)

Answer 2

您可以尝试使用子查询（首先从group_assign中获取您想要的内容），如下所示：

SELECT
   a.GROUP_ID,
   a.GROUP_DESC, 
   CASE WHEN b.GROUP_ID IS NULL THEN '0' ELSE '1' end as status 
FROM dbo.GROUP_MASTER A 
LEFT JOIN (select GROUP_ID, LOG_NAME from dbo.GROUP_ASSIGN where LOG_NAME LIKE 'ACCOUNT') B ON (B.GROUP_ID = a.GROUP_ID)

WHERE 1个字段的条款

2 个答案: