mysql语句写法（左连与子查询结合）实战

select

c.card_number,

c.card_name,

t.type_name,

c.card_discount,

t.type_low,

c.card_integral,

(c.card_recharge_balance+c.card_give_balance) as num,

v.people,

c.card_time

from

`vip_card` as c

left join

(

select

count(vipid) as people,

card_number

from vip

group by card_number

) as v

on

c.card_number=v.card_number

left join

`vip_type` as t

on

c.type_id=t.type_id

where

c.store_key='556655';