Question

我的表格如下：

ID  | Advert_id  | Iso_code
----|------------|-----------
1   | 22         | en_US
2   | 22         | de_DE
3   | 11         | zh_CE
4   | 11         | nl_NL

我需要返回ID，例如我有Advert_ID = 22 ID 1和2 iso_code = en_US和de_DE但Advert_ID有iso_code = en_US id = 1仅返回Advert_ID = 11如果不返回所有ID（iso_code = en_US没有Id，那么返回display: inline-block 3和4）

Answer 1

使用or not exists()

select *
from t
where (t.iso_code = 'en_US' 
     or not exists (
        select 1 
        from t as i
        where t.Advert_id = i.Advert_id
          and i.iso_code = 'en_US')
      )

测试设置：http://rextester.com/SGH43248

返回：

+----+-----------+----------+
| id | advert_id | iso_code |
+----+-----------+----------+
|  1 |        22 | en_US    |
|  3 |        11 | zh_CE    |
|  4 |        11 | nl_NL    |
+----+-----------+----------+

Answer 2

来自你的评论：

我需要选择所有＆＃34; Advarte_ID＆＃34;并检查iso_code if =＆＃39; en_US＆＃34;只返回带有＆＃39; en_US＆＃39;

如果我理解你，那将有所帮助：

SELECT ID
FROM YourTablName
WHERE iso_code = 'en_US';

这将仅返回Advert_ID s，其中包含`iso_code =＆＃39; en_US＆＃39;。

<强>更新

IF EXISTS (SELECT * FROM YourTable WHERE iso_code = 'en_US')
BEGIN
SELECT ID
FROM YourTablName
WHERE iso_code = 'en_US';
END
  ELSE
    BEGIN
      SELECT ID
      FROM YourTable;
    END

SQL简单请求

2 个答案: