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PDO Binding Values for MySQL IN Statement
You're facing an issue when using PDO to bind an array of values to a MySQL IN statement. Your goal is to execute the query as follows:
SELECT users.id FROM users JOIN products ON products.user_id = users.id WHERE products IN (1,2,3,4,5,6,7,8)
However, PDO is converting the bound values into a comma-separated string, resulting in the following erroneous query:
SELECT users.id FROM users JOIN products ON products.user_id = users.id WHERE products IN ('1,2,3,4,5,6,7,8')
You've tried using a custom function to split the comma-separated string inside the query itself, but this isn't an optimal solution.
Solution 1: Constructing the Query Manually
As suggested in a previous question, you can manually construct the query by concatenating the placeholders for each IN clause value. For example:
$products = array(1,2,3,4,5,6,7,8); $placeholders = array_fill(0, count($products), '?'); $sql = "SELECT users.id FROM users JOIN products ON products.user_id = users.id WHERE products IN (" . implode(',', $placeholders) . ")"; $stmt = $pdo->prepare($sql); $stmt->execute($products);
Solution 2: Using find_in_set()
You can use the find_in_set() function to match a value against a comma-separated string. However, this approach may have performance issues with large datasets, as it requires converting every value in the table to a character type.
$products = array(1,2,3,4,5,6,7,8); $sql = "SELECT users.id FROM users JOIN products ON products.user_id = users.id WHERE find_in_set(cast(products.id as char), '" . implode(',', $products) . "') > 0"; $stmt = $pdo->prepare($sql); $stmt->execute();
Solution 3: Creating a User Defined Function
The best solution is to create a user defined function (UDF) that splits the comma-separated string. This is a relatively complex solution, but it provides the best performance for IN clauses with variable-sized lists.
Refer to the provided link for instructions on creating the UDF.
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