mysqli_store_result

Замечание: Although it is always good practice to free the memory used by the result of a query using the mysqli_free_result() function, when transfering large result sets using the mysqli_store_result() this becomes particularly important.

Замечание: mysqli_store_result() returns FALSE in case the query didn't return a result set (if the query was, for example an INSERT statement). This function also returns FALSE if the reading of the result set failed. You can check if you have got an error by checking if mysqli_error() doesn't return an empty string, if mysqli_errno() returns a non zero value, or if mysqli_field_count() returns a non zero value. Also possible reason for this function returning FALSE after successfull call to mysqli_query() can be too large result set (memory for it cannot be allocated). If mysqli_field_count() returns a non-zero value, the statement should have produced a non-empty result set.