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 @count = sum(data) from
(
select count(*) as data from #tempregion
union
select count(*) as data from #tempmetro
union
select count(*) as data from #tempcity
union
select count(*) as data from #tempzips
) a
其他回答
SELECT (
SELECT COUNT(*)
FROM tbl1
)
+
(
SELECT COUNT(*)
FROM tbl2
)
as TotalCount
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 (select count(*) from tab1) count_1, (select count(*) from tab2) count_2 from dual;
为了完整起见,这个查询将创建一个查询,为您提供给定所有者的所有表的计数。
select
DECODE(rownum, 1, '', ' UNION ALL ') ||
'SELECT ''' || table_name || ''' AS TABLE_NAME, COUNT(*) ' ||
' FROM ' || table_name as query_string
from all_tables
where owner = :owner;
输出是这样的
SELECT 'TAB1' AS TABLE_NAME, COUNT(*) FROM TAB1
UNION ALL SELECT 'TAB2' AS TABLE_NAME, COUNT(*) FROM TAB2
UNION ALL SELECT 'TAB3' AS TABLE_NAME, COUNT(*) FROM TAB3
UNION ALL SELECT 'TAB4' AS TABLE_NAME, COUNT(*) FROM TAB4
然后你可以运行它来得到你的计数。有时它只是一个方便的脚本。
SELECT (
SELECT COUNT(*)
FROM tab1
) AS count1,
(
SELECT COUNT(*)
FROM tab2
) AS count2
FROM dual