从多个表中选择count(*)

我如何从两个不同的表(叫他们tab1和tab2)选择计数(*)有作为结果:

Count_1   Count_2
123       456

我试过了:

select count(*) Count_1 from schema.tab1 union all select count(*) Count_2 from schema.tab2

但我所拥有的只有:

Count_1
123
456

当前回答

选择 (select count() from tab1 where field like 'value') + (select count() from tab2 where field like 'value') 数

其他回答

与不同的表进行JOIN

SELECT COUNT(*) FROM (  
SELECT DISTINCT table_a.ID  FROM table_a JOIN table_c ON table_a.ID  = table_c.ID   );

我很快想到了:

Select (select count(*) from Table1) as Count1, (select count(*) from Table2) as Count2

注意:我在SQL Server中测试了这个，所以从Dual是不必要的(因此存在差异)。

    select 
    t1.Count_1,t2.Count_2
    from 
(SELECT count(1) as Count_1 FROM tab1) as t1, 
(SELECT count(1) as Count_2 FROM tab2) as t2

Declare @all int
SET @all = (select COUNT(*) from tab1) + (select count(*) from tab2)
Print @all

SELECT (select COUNT(*) from tab1) + (select count(*) from tab2)

作为附加信息，要在SQL Server中完成同样的事情，您只需要删除查询的“FROM dual”部分。

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