MySQL 过滤器，在哪里

Question

我的 mysql 过滤器有问题。如果用户有一个空字段，则查询不起作用。我该如何解决这个问题，如果未选择类型，我已尝试在类型处发送“NULL”，但这也不起作用。

$STH = $DBH->query("
SELECT * 
WHERE store ='$type' and sdn='$status' and price>='$price_s' and price<='$price_e' ORDER BY id DESC LIMIT $setlimit");


$STH = $DBH->query("
SELECT * 
WHERE store ='$type' and sdn='$status' and price>='$price_s' and price<='$price_e' ORDER BY id DESC LIMIT $setlimit");

Answer 1

似乎缺少 from，例如如果表是销售，请尝试

$STH = $DBH->query("
SELECT * from sales 
WHERE store='$type' and sdn='$status' and price>='$price_s' and price<='$price_e' 
ORDER BY id DESC LIMIT $setlimit");


$STH = $DBH->query("
SELECT * from sales
WHERE store='$type' and sdn='$status' and price>='$price_s' and price<='$price_e' 
ORDER BY id DESC LIMIT $setlimit");