绑定“非空".在PDO中? [英] Binding "not null" in PDO?

问题描述

我最近发现您可以在PDO中绑定空值:

I recently found out that you can bind null values in PDO:

$stmt = $db->prepare('SELECT * FROM foo WHERE bar = :bar');
$stmt->execute(array(':bar'=>null));
$foo = $stmt->fetchAll(PDO::FETCH_OBJ);

这将成功地从数据库中提取所有foo，其中bar列为空.

This would successfully fetch all foo from the database, where the bar column is null.

但是，我现在想做相反的事情.我想获取bar列为 not null的所有列.

However, I would now like to do the opposite. I would like to fetch all columns where the bar column is not null.

我知道我可以简单地将bar = :bar替换为bar IS NOT NULL.但是，我想避免这种情况，而是通过准备好的语句来完成，因为有时我必须动态地构建查询字符串，而必须手动进行查询，这会带来很多额外的工作.

I am aware I could simply replace bar = :bar with bar IS NOT NULL. However, I would like to avoid that, and instead do it through prepared statements, because I sometimes have to build the query string dynamically and having to do it manually would be a lot of extra work.

这可能吗?

推荐答案

您不能绑定"NOT NULL".您只能绑定值. "IS NOT NULL"不是值，它是完全不同的查询语法.您只需要动态地构建查询，值绑定就不能帮助您实现这一点:

You cannot bind "NOT NULL". You can only bind values. "IS NOT NULL" is not a value, it's completely different query syntax. You will simply have to dynamically build your query, value binding cannot help you with that:

$query = 'SELECT ... WHERE ';
if (/* condition is NOT NULL */) {
    $query .= 'foo IS NOT NULL';
    $stmt = $db->prepare($query);
} else {
    $query .= 'foo = :foo';
    $stmt = $db->prepare($query);
    $stmt->bindValue('foo', $foo);
}
$stmt->execute();

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