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
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
SELECT (
SELECT COUNT(*)
FROM tab1
) AS count1,
(
SELECT COUNT(*)
FROM tab2
) AS count2
FROM dual
其他回答
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)。
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。
其他略有不同的方法:
with t1_count as (select count(*) c1 from t1),
t2_count as (select count(*) c2 from t2)
select c1,
c2
from t1_count,
t2_count
/
select c1,
c2
from (select count(*) c1 from t1) t1_count,
(select count(*) c2 from t2) t2_count
/
这是我的分享
选项1 -计数从相同的域从不同的表
select distinct(select count(*) from domain1.table1) "count1", (select count(*) from domain1.table2) "count2"
from domain1.table1, domain1.table2;
选项2 -同一表从不同的域计数
select distinct(select count(*) from domain1.table1) "count1", (select count(*) from domain2.table1) "count2"
from domain1.table1, domain2.table1;
选项3 -计数从不同的领域为同一表与“联合所有”有行计数
select 'domain 1'"domain", count(*)
from domain1.table1
union all
select 'domain 2', count(*)
from domain2.table1;
享受SQL,我总是这样做:)
select (select count(*) from tab1) count_1, (select count(*) from tab2) count_2 from dual;