Question

如何将这两个查询合并为一个，这样我就不必一次又一次地重复相同的行？

if(empty($cat_id))
{
    $sql = "
    SELECT *
    FROM root_category_contacts
    ORDER by cat_order ASC
    ";

    $items_category = $connection->fetch_all($sql);
}
else
{
    $sql = "
    SELECT *
    FROM root_category_contacts
    WHERE root_category_contacts.cat_id != ?
    ORDER by cat_order ASC
    ";

    $items_category = $connection->fetch_all($sql,array($cat_id));
}

当我没有WHERE时，我不需要cat_id子句。

可行吗？

Answer 1

测试是否？为null或等于cat_id。像这样：

根据xdazz的评论

修改。假设cat_id＆gt; 0

$sql = "
SELECT *
FROM root_category_contacts
WHERE root_category_contacts.cat_id != ?
ORDER by cat_order ASC"

if(empty($cat_id)) {
    $cat_id = 0;
}

$items_category = $connection->fetch_all($sql,array($cat_id));

Answer 2

if(empty($cat_id)) $where = "";
else $where = "WHERE root_category_contacts.cat_id != '$cat_id'"

$sql = "
    SELECT *
    FROM root_category_contacts
    $where
    ORDER by cat_order ASC
    ";

$items_category = $connection->fetch_all($sql);

MySQL：结合两个重复查询以使WHERE子句动态化

2 个答案: