寻找Mysql查询

Question

我有以下3个字段的mysql表：

- vouchercode: Unique KEY
- voucherstatus: 1 for unused voucher, 3 for used voucher
- partnerId

我想显示使用和未使用的优惠券数量。\ n伙伴ID

Example :- table data 
PartnerId voucherstaus  vouchercode(unique)
1          1
1          3 
1          1
2          3
2          3
2          1


Result:
PartnerId  usedvouchers unusedvouchers
1          1             2
2          2             1

请帮我解决mysql查询问题。似乎我必须使用子查询和分组不起作用。提前致谢

Answer 1

SELECT  partnerID,
        SUM(CASE WHEN voucherstatus = 1 THEN 1 ELSE 0 END) unusedvouchers,
        SUM(CASE WHEN voucherstatus = 3 THEN 1 ELSE 0 END) usedvouchers 
FROM    data
GROUP   BY partnerID

• SQLFiddle Demo
• SQLFiddle Demo (will work only in MySQL)

Answer 2

select PartnerId, SUM(case when  voucher_status =1 then 1 else 0 end) as unused, sum(case when  voucher_status =3 then 1 else 0 end) as used from Voucher group by PartnerID;

sqlfiddle *demo*