将三个表之间的count(*)求和

Question

我想对 3 个表之间的计数求和。我已经添加了三个输入字段来每次给出一个特定的日期，但我正在努力研究如何 SUM the COUNTS(*)

select count(*)
from db.table1
where call_date = ${var:call_date};

select count(*)
from db.table2
where call_date = ${var:call_date};

select count(*)
from  db.table3
where call_date= ${var:call_date};

提前致谢

Answer 1

UNION ALL 中选。 SUM()结果。

select sum(cnt) from
(
    select count(*) cnt
    from db.table1
    where call_date = ${var:call_date}
    UNION ALL
    select count(*)
    from db.table2
    where call_date = ${var:call_date}
    UNION ALL
    select count(*)
    from  db.table3
    where call_date= ${var:call_date}
) dt

Answer 2

您可以简单地将它们用作子查询，如下所示：

select (select count(*) from db.table1 where call_date = ${var:call_date}) 
+ (select count(*) from db.table2 where call_date = ${var:call_date})
+ (select count(*) from  db.table3 where call_date= ${var:call_date}) 
as rslt;

将三个表之间的count(*)求和

Sum the count(*) of between three tables

sql

impala