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使用一条sql查询多个表中的记录数

时间:2021-07-01 10:21:17 帮助过:18人阅读

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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