[MYSQL] 不同資料表 欄位相乘

[SKY1225 (nothing)]

兩個TABLE

Table A

欄位有

ID  cost

Table B

ID  use

程式碼

$sqlstr= "select*from B INNER JOIN find on B.ID = A.ID ";

僅能分別帶出 cost 和 use

該在哪裡修改才能讓 cost*use呢...


--
※ 發信站: 批踢踢實業坊(ptt.cc) 
◆ From: 59.124.165.175
→ lbeeon:select (a.cost * b.use) as cost from....
→ SKY1225:再請教一下 要如何再把他們不同ID的cost*use相加呢...
→ lbeeon:select sum(a.cost*b.use) as cost from.... group by ID