COM_STMT_PREPARE

Creates a prepared statement for the passed query string.

The server returns a COM_STMT_PREPARE Response which contains a statement-id which is ised to identify the prepared statement.

Payload

Type	Name	Description
int<1>	command	0x16: COM_STMT_PREPARE
string<EOF>	query	The query to prepare

Example

1c 00 00 00 16 53 45 4c    45 43 54 20 43 4f 4e 43    .....SELECT CONC
41 54 28 3f 2c 20 3f 29    20 41 53 20 63 6f 6c 31    AT(?, ?) AS col1

Returns

COM_STMT_PREPARE_OK on success, ERR_Packet otherwise

See also

mysqld_stmt_prepare, mysql_stmt_precheck, Prepared_statement, mysql_stmt_prepare, mysql_stmt_init

Note

As LOAD DATA isn't supported by COM_STMT_PREPARE yet, no LOCAL INFILE Request is expected here. This is unlike COM_QUERY Response.

COM_STMT_PREPARE Response

If COM_STMT_PREPARE succeeded, it sends a COM_STMT_PREPARE_OK

COM_STMT_PREPARE_OK

Payload of the first packet

Type	Name	Description
int<1>	status	0x00: OK: Ignored by cli_read_prepare_result
int<4>	statement_id	statement ID
int<2>	num_columns	Number of columns
int<2>	num_params	Number of parameters
int<1>	reserved_1	[00] filler
if (packet_lenght > 12) {
int<2>	warning_count	Number of warnings
if capabilities & CLIENT_OPTIONAL_RESULTSET_METADATA {
int<1>	metadata_follows	Flag specifying if metadata are skipped or not. See enum_resultset_metadata
} – CLIENT_OPTIONAL_RESULTSET_METADATA {
} – packet_lenght > 12

if num_params > 0 and CLIENT_OPTIONAL_RESULTSET_METADATA is not set or if medatdata_follows is RESULTSET_METADATA_FULL num_params packets will follow. Then a EOF_Packet will be transmitted, provided that CLIENT_DEPRECATE_EOF is not set.

Parameter definition block

Type	Name	Description
num_params * Column Definition
if (not capabilities & CLIENT_DEPRECATE_EOF) {
EOF_Packet
} –CLIENT_DEPRECATE_EOF

if num_columns > 0 and CLIENT_OPTIONAL_RESULTSET_METADATA is not set or if medatdata_follows is RESULTSET_METADATA_FULL num_columns packets will follow. Then a EOF_Packet will be transmitted, provided that CLIENT_DEPRECATE_EOF is not set.

Column definition block

Type	Name	Description
num_columns * Column Definition
if (not capabilities & CLIENT_DEPRECATE_EOF) {
EOF_Packet
} –CLIENT_DEPRECATE_EOF

Example

for a prepared query like SELECT CONCAT(?, ?) AS col1 and no CLIENT_OPTIONAL_RESULTSET_METADATA

0c 00 00 01 00 01 00 00    00 01 00 02 00 00 00 00|   ................
17 00 00 02 03 64 65 66    00 00 00 01 3f 00 0c 3f    .....def....?..?
00 00 00 00 00 fd 80 00    00 00 00|17 00 00 03 03    ................
64 65 66 00 00 00 01 3f    00 0c 3f 00 00 00 00 00    def....?..?.....
fd 80 00 00 00 00|05 00    00 04 fe 00 00 02 00|1a    ................
00 00 05 03 64 65 66 00    00 00 04 63 6f 6c 31 00    ....def....col1.
0c 3f 00 00 00 00 00 fd    80 00 1f 00 00|05 00 00    .?..............
06 fe 00 00 02 00                                     ...

Example

for a a query without parameters and resultset like DO 1 and no CLIENT_OPTIONAL_RESULTSET_METADATA :

0c 00 00 01 00 01 00 00    00 00 00 00 00 00 00 00

See also

cli_read_prepare_result, mysql_stmt_prepare, send_statement, THD::send_result_metadata