为不同表中的另一个字段选择sum multiply字段,这是相等的

ykejflvf  于 2021-06-24  发布在  Mysql
关注(0)|答案(1)|浏览(272)

我通过这个例子来解释:
第一个表是产品:

id|price|
1   30

第二张table是仓库:

id|id_product|amount|sell_price|
1       1       1        50

我要乘以金额(仓库表)*价格(产品表),其中id(仓库表)=id(产品表)

$result_sum_ricavo = mysqli_query($link,"SELECT SUM(total_sum) FROM (p.prezzo * w.quantita as total_sum FROM prodotti p JOIN storico_magazzino w on p.id = w.id_collo AND w.causale='consegna' AND w.tipo='prodotto' AND w.importo_documento>0)");
$row_sum_ricavo = mysqli_fetch_assoc($result_sum_ricavo); 
$guadagno = $row_sum_ricavo["total_sum"];

我有一个错误:
mysqli\u fetch\u assoc()期望参数1是mysqli\u result,布尔值在

ruarlubt

ruarlubt1#

SELECT
 SUM(total_sum)
FROM (
    SELECT p.price * w.amount as total sum
    FROM products p JOIN warehouse w on p.id = w.id
)

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