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使用一条sql查询多个表中的记录数

2024-11-24 10:44:02   202人阅读

方法一：

 select t1.num1,t2.num2,t3.num3 from   (select count(*) num1 from table1) t1,  (select count(*) num2 from table2) t2,  (select count(*) num3 from table3) t3

方法二：

select sum(t.num1),sum(t.num2),sum(t.num3) from (    select count(*) num1,0 as num2,0 as num3 from table1   union     select 0 as num1,count(*) num2,0 as num3 from table2  union     select 0 as num1,0 as num2,count(*) num3 from table3) t

 

使用一条sql查询多个表中的记录数


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