Mysql 如何在一个sql查询中计算多个表中的行数

我遇到了一个问题，即必须从多个表中获取行计数，其中包含where

例如：

你可以用UNION

SELECT COUNT(*) FROM table1
UNION
SELECT COUNT(*) FROM table1 where condition;
UNION
SELECT COUNT(*) FROM table2;
UNION
SELECT COUNT(*) FROM table3 where condition;

通过以下查询，您可以添加额外的字段来查找您得到的行

SELECT "COND-1" AS TITLE, COUNT(*) FROM table1
UNION
SELECT "COND-2" AS TITLE, COUNT(*) FROM table1 where condition;
UNION
SELECT "COND-3" AS TITLE, COUNT(*) FROM table2;
UNION
SELECT "COND-4" AS TITLE, COUNT(*) FROM table3 where condition;

SELECT "COND-1" AS TITLE, COUNT(*) FROM table1
UNION
SELECT "COND-2" AS TITLE, COUNT(*) FROM table1 where condition;
UNION
SELECT "COND-3" AS TITLE, COUNT(*) FROM table2;
UNION
SELECT "COND-4" AS TITLE, COUNT(*) FROM table3 where condition;