我试图计算以下三个结果的总和,但只得到一个结果的计数。
$sql = "(SELECT COUNT(*) FROM table1 WHERE somecondition)
UNION
(SELECT COUNT(*) FROM table2 WHERE somecondition)
UNION
(SELECT COUNT(*) FROM table3 WHERE somecondition)";
有人能帮忙吗?谢谢
最佳答案
查询将返回三行,其中包含三个单独的计数。
你想要的是
select sum(c) from (
(SELECT COUNT(*) AS c FROM table1 WHERE somecondition)
UNION
(SELECT COUNT(*) FROM table2 WHERE somecondition)
UNION
(SELECT COUNT(*) FROM table3 WHERE somecondition)
) all_three
关于mysql - 选择计数(*)没有给出正确的计数,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/10345040/