Question

这是我的问题：

SELECT COUNT(*) FROM jos_mls AS mls 
    INNER JOIN jos_activeagents AS active ON active.AGENTUID = mls.MSTLISTBRD
    AND mls.MSTACTSTA = 'Active' OR mls.MSTACTSTA = 'Keep Showing';

这些表非常大，因此很难显示表结构。

当我在没有AND mls.MSTACTSTA = 'Active' OR mls.MSTACTSTA = 'Keep Showing'的情况下运行计数时，我得到了预期的结果（大约500）。但是，当我想用这些参数过滤掉它时，它会重新获得25000+个结果，当它应该低于500时。

我认为这是一个语法问题，但查找类似的问题，我无法提出解决方案。

Answer 1

使用WHERE子句

SELECT COUNT(*) FROM jos_mls AS mls 
    INNER JOIN jos_activeagents AS active ON active.AGENTUID = mls.MSTLISTBRD
    WHERE mls.MSTACTSTA = 'Active' OR mls.MSTACTSTA = 'Keep Showing';

Answer 2

SELECT COUNT(*) 
  FROM jos_mls mls 
  JOIN jos_activeagents active 
    ON active.AGENTUID = mls.MSTLISTBRD
   AND (mls.MSTACTSTA = 'Active' OR mls.MSTACTSTA = 'Keep Showing');

或

SELECT COUNT(*) 
  FROM jos_mls mls 
  JOIN jos_activeagents active 
    ON active.AGENTUID = mls.MSTLISTBRD
   AND mls.MSTACTSTA IN('Active','Keep Showing');

Answer 3

AND优先于OR，因此您应该在条件的第二部分周围使用括号来获得所需的输出：

SELECT COUNT(*) FROM jos_mls AS mls 
    INNER JOIN jos_activeagents AS active ON active.AGENTUID = mls.MSTLISTBRD
    AND (mls.MSTACTSTA = 'Active' OR mls.MSTACTSTA = 'Keep Showing');

您获得的行数远远超出预期的原因是您运行的实际查询与此相同：

SELECT COUNT(*) FROM jos_mls AS mls 
    INNER JOIN jos_activeagents AS active ON (active.AGENTUID = mls.MSTLISTBRD
    AND mls.MSTACTSTA = 'Active') OR mls.MSTACTSTA = 'Keep Showing';

mysql计数显示比预期更多的结果

3 个答案: