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
1条答案
按热度按时间ruarlubt1#