如何获得这三个COUNTS（）的SUM？

Question

这是我的疑问：

SELECT (SELECT COUNT(`id`) FROM `table1` WHERE `id` = '1') AS `count1`,
(SELECT COUNT(`id`) FROM `table2` WHERE `id` = '1') AS `count2`,
(SELECT COUNT(`id`) FROM `table3` WHERE `id` = '1') AS `count3`

如何获得count1, count2, count3的总和？

我有什么方法可以在上面的查询中

Answer 1

不确定。只需将值加在一起：

SELECT (SELECT COUNT(`id`) FROM `table1` WHERE `id` = '1') +
       (SELECT COUNT(`id`) FROM `table2` WHERE `id` = '1') +
       (SELECT COUNT(`id`) FROM `table3` WHERE `id` = '1') AS `sum` ...