Question

我试图只选择三个组中的对象（1,2,3）使用“WHERE gid IN（1,2,3）”选择我得到OR选择。我需要的是AND选择。

OBJECT_TABLE AS o  
id | field1 | field2 | ...  

 VALUES  
 1, a, b  
 2, c, d  
 3, e, f  
 ...


GROUP_XREF_TABLE AS gx   
 oid | gid  

VALUES  
1, 1  
1, 2  
1, 3  
2, 2  
3, 1  
3, 2  
...


SELECT DISTINCT o.id, gx.gid FROM `OBJECT_TABLE`  AS o
LEFT JOIN `GROUP_XREF_TABLE` AS gx ON o.id = gx.oid
WHERE gx.gid IN (1,2,3)

这将输出所有行。我需要一个WHERE子句，它只输出对象id为1的行，因为只有那个对象在所有三个组中。

它是较大选择的一部分，所以重要的是这应该只在where语句中完成（如果需要，子选择应该没问题）。

Answer 1

下面的子选择将找到那些在gx中有3行的oid：

SELECT o.id, gx.gid FROM `OBJECT_TABLE`  AS o
LEFT JOIN `GROUP_XREF_TABLE` AS gx ON o.id = gx.oid
WHERE gx.oid IN (
    SELECT oid FROM GROUP_XREF_TABLE as gx2 
     GROUP BY oid
    HAVING count(*) = 3)

Answer 2

试试这个

   SELECT  o.id, gx.gid FROM `OBJECT_TABLE`  AS o
   LEFT JOIN `GROUP_XREF_TABLE` AS gx ON o.id = gx.oid
   WHERE gx.gid IN (1,2,3)
   group by gx.gid

DEMO HERE

使用逻辑AND语句选择WHERE IN

2 个答案: