# COM\_STMT\_PREPARE

Prepares a statement on the server.

{% hint style="info" %}
Not all statements can be prepared. See [PREPARE](https://mariadb.com/docs/server/sql-statements/prepared-statements/prepare-statement#permitted-statements) for a list of statements that can be prepared.
{% endhint %}

## Implemented by

* [mariadb\_stmt\_execute\_direct()](https://app.gitbook.com/s/CjGYMsT2MVP4nd3IyW2L/mariadb-connector-c/api-prepared-statement-functions/mariadb_stmt_execute_direct)
* [mysql\_stmt\_prepare()](https://app.gitbook.com/s/CjGYMsT2MVP4nd3IyW2L/mariadb-connector-c/api-prepared-statement-functions/mysql_stmt_prepare)

## Fields

* [int<1>](https://mariadb.com/docs/server/reference/protocol-data-types#fixed-length-integers) `0x16` `COM_STMT_PREPARE` header
* [string\<EOF>](https://mariadb.com/docs/server/reference/protocol-data-types#end-of-file-length-strings) SQL Statement

## Example

```
1F 00 00 00 16 53 45 4C 45 43 54 20 2A 20 46 52  .....SELECT * FR
1F 4D 20 74 65 73 74 5F 62 69 6E 64 5F 72 65 73  OM test_bind_res
75 6C 74                                         ult
```

## Response

If something goes wrong, the server sends an [ERR\_Packet](https://mariadb.com/docs/server/reference/clientserver-protocol/4-server-response-packets/err_packet). If the command succeeds, different packets are received:

* [COM\_STMT\_PREPARE\_OK](#COM_STMT_PREPARE_OK).
* If number of parameters (count of `?` placeholders) > `0`:
  * For each parameter:
    * [column definition packet](https://mariadb.com/docs/server/reference/clientserver-protocol/4-server-response-packets/result-set-packets).
  * If !`DEPRECATE_EOF` [eof\_packet](https://mariadb.com/docs/server/reference/clientserver-protocol/4-server-response-packets/eof_packet).
* If prepared statement returns result set and number of result set columns > `0`:
  * For each column:
    * [column definition packet](https://mariadb.com/docs/server/reference/clientserver-protocol/4-server-response-packets/result-set-packets).
  * If !`DEPRECATE_EOF` [eof\_packet](https://mariadb.com/docs/server/reference/clientserver-protocol/4-server-response-packets/eof_packet).

### COM\_STMT\_PREPARE\_OK

* [int<1>](https://mariadb.com/docs/server/reference/protocol-data-types#fixed-length-integers) `0x00` `COM_STMT_PREPARE_OK` header.
* [int<4>](https://mariadb.com/docs/server/reference/protocol-data-types#fixed-length-integers) statement ID.
* [int<2>](https://mariadb.com/docs/server/reference/protocol-data-types#fixed-length-integers) number of columns in the returned result set (or 0 if statement does not return result set).
* [int<2>](https://mariadb.com/docs/server/reference/protocol-data-types#fixed-length-integers) number of prepared statement parameters ('?' placeholders).
* [string<1>](https://mariadb.com/docs/server/reference/protocol-data-types#fixed-length-strings) -not used-
* [int<2>](https://mariadb.com/docs/server/reference/protocol-data-types#fixed-length-integers) number of warnings.

<sub>*This page is licensed: CC BY-SA / Gnu FDL*</sub>

{% @marketo/form formId="4316" %}