Question

我有4张桌子：

ADS：ID，文字，数字

TABLE2：id，user_id，数字
TABLE3：id，user_id，数字
TABLE4：id，user_id，数字

user_id不是唯一的。可以存在与否。

输出我希望：
如果ADS表的数量等于TABLE1或TABLE2或TABLE3的数字，则仅显示文字的。

我试过了：

SELECT ADS.text FROM ADS 
LEFT JOIN TABLE2 ON TABLE2.user_id = ? 
LEFT JOIN TABLE3 ON TABLE3.user_id = ? 
LEFT JOIN TABLE4 ON TABLE4.user_id = ? 
WHERE ADS.number = TABLE2.number OR 
ADS.number = TABLE3.number OR 
ADS.number = TABLE4.number 
GROUP BY ADS.id

和

SELECT * FROM 
(
SELECT 
ADS.text FROM ADS 
LEFT JOIN TABLE2 ON TABLE2.user_id = ? 
LEFT JOIN TABLE3 ON TABLE3.user_id = ? 
LEFT JOIN TABLE4 ON TABLE4.user_id = ? 
WHERE ADS.number = TABLE2.number OR 
ADS.number = TABLE3.number OR 
ADS.number = TABLE4.number 

UNION ALL

SELECT 
ADS.text FROM ADS 
LEFT JOIN TABLE2 ON TABLE2.user_id = ? 
LEFT JOIN TABLE3 ON TABLE3.user_id = ? 
LEFT JOIN TABLE4 ON TABLE4.user_id = ? 
WHERE ADS.number = TABLE2.number OR 
ADS.number = TABLE3.number OR 
ADS.number = TABLE4.number 
) request 
ORDER BY ADS.id

$reponse->execute(array($_SESSION['id'],$_SESSION['id'],$_SESSION['id']));

我的输出总是太多或不够......

Answer 1

这样做你想要的吗？

SELECT ADS.text
FROM ADS a
WHERE EXISTS (SELECT 1 FROM TABLE2 t WHERE t.user_id = ? AND t.number = a.number) OR
      EXISTS (SELECT 1 FROM TABLE3 t WHERE t.user_id = ? AND t.number = a.number) OR
      EXISTS (SELECT 1 FROM TABLE4 t WHERE t.user_id = ? AND t.number = a.number);

Mysql JOIN一个表有多个表

1 个答案: