Question

是否可以将以下查询作为一个查询执行？

[代码]

select count(*) from tableA;
select count(*) from tableB;
select count(*) from tableC;
select count(*) from tableD;

[/代码]

即。结果是这样的

|TablA|TableB|TableC|TableD|
|50   |300   |30    |9|

由于

Answer 1

select * from
(select count(*) from tableA),
(select count(*) from tableB),
(select count(*) from tableC),
(select count(*) from tableD);

Answer 2

是

select count(*) from tableA;
union all
select count(*) from tableB;
union all
select count(*) from tableC;
union all
select count(*) from tableD;

Answer 3

以下内容适用于任何DBMS。

SELECT *
FROM   (select count(*) as tableA from tableA) a
       full outer join (select count(*) as tableB from tableB) b
       full outer join (select count(*) as tableC from tableC) c
       full outer join (select count(*) as tableD from tableD) d

Answer 4

试试这个：的

用一个作为（选择计数（1）作为counterA，1作为假表从表A），两个为（选择count（1）作为counterB，1作为来自tableB的虚拟），三个为（选择count（1）作为counterC，1作为来自tableC的伪），四为（选择count（1）作为counterD，1作为tableD的伪）

选择one.counterA，two.counterB，three.counterC，four.counterD from one，two，three，four，其中one.dummy = two.dummy和two.dummy = three.dummy和three.dummy = four.dummy; < / b>

合并多个oracle查询以生成一个结果

4 个答案: