sql - 一个语句中的多个查询

Question

我需要在 PostgreSQL 中将以下两个查询合并到一个语句中。

select count(*) as REDEEMTOTALUSED 
from voucher 
where campaign_id='123' and redeemcount>0;

select count(*) as REDEEMTOTALUNUSED 
from voucher 
where campaign_id='123' and redeemcount=0;

结果应该如下所示。

REDEEMTOTALUSED | REDEEMTOTALUNUSED1               | 9                

这可能吗？

Answer 1

请尝试:

select 
    (select count(*) as REDEEMTOTALUSED 
     from voucher 
     where campaign_id='123' and redeemcount>0) AS REDEEMTOTALUSED ,
    (select count(*) as REDEEMTOTALUNUSED 
     from voucher 
     where campaign_id='123' and redeemcount=0) AS REDEEMTOTALUNUSED 

或另一种方式:

    SELECT 
       SUM(CASE 
             WHEN redeemcount>0 THEN 1 
             ELSE 0 
           END) as REDEEMTOTALUSED ,
       SUM(CASE 
             WHEN redeemcount=0 THEN 1 
             ELSE 0
           END) as REDEEMTOTALUNUSED 
    from 
       voucher 
    WHERE
       campaign_id='123'