mysqlistmtbindresult

MySQLi_stmt_bind_result is a procedural function provided by the MySQLi extension in PHP for binding variables to columns in a prepared statement's result set. The function signature is

mysqli_stmt_bind_result ( mysqli_stmt $stmt , mixed &$var1 [, mixed &$... ] ) : bool

It takes a mysqli_stmt object and an arbitrary number of variables passed by reference. Each supplied variable corresponds to a column returned by a SELECT query that has been executed with the prepared statement. After calling mysqli_stmt_execute, the client invokes mysqli_stmt_bind_result to associate each column with a PHP variable. Subsequent calls to mysqli_stmt_fetch fetch one row at a time, populating the bound variables with the column values for that row.

The function returns TRUE on success or FALSE if binding fails. Binding is typically performed once per prepared statement; the same statement can be reused to fetch multiple rows because the bound variables are reused each fetch cycle. The variables are bound by reference, so they must persist until the statement is closed or the script ends. Unbound variables remain NULL for that column.

Common pitfalls include attempting to bind fewer variables than there are columns, which causes errors, or binding complex types such as BLOBs without specifying buffer lengths. Additionally, using mysqli_stmt_store_result before binding is unnecessary and may consume extra memory.

MySQLi_stmt_bind_result is part of a pair of functions: mysqli_stmt_bind_param for input parameters and mysqli_stmt_fetch for retrieving rows. These functions together enable efficient, safe prepared statement handling, helping guard against SQL injection and improving performance through query caching.