MySQL  8.0.26
Source Code Documentation
COM_STMT_EXECUTE

COM_STMT_EXECUTE asks the server to execute a prepared statement as identified by statement_id.

It sends the values for the placeholders of the prepared statement (if it contained any) in Binary Protocol Value form. The type of each parameter is made up of two bytes:

  • the type as in enum_field_types
  • a flag byte which has the highest bit set if the type is unsigned [80]

The num_params used for this packet reffers to num_params of the COM_STMT_PREPARE_OK of the corresponsing prepared statement.

The server will use the first num_params (from prepare) parameter values to satisfy the positional anonymous question mark parameters in the statement executed regardless of whether they have names supplied or not. The rest num_remaining_attrs parameter values will just be stored into the THD and if they have a name they can later be accessed as query attributes. If any of the first num_params parameter values has a name supplied they could then be accessed as a query attribute too. If supplied, parameter_count will overwrite the num_params value by eventually adding a non-zero num_params_remaining value to the original num_params.

Returns
COM_STMT_EXECUTE Response
Payload
TypeNameDescription
int<1> status [0x17] COM_STMT_EXECUTE
int<4> statement_id ID of the prepared statement to execute
int<1> flags Flags. See enum_cursor_type
int<4> iteration_count Number of times to execute the statement. Currently always 1.
if (num_params > 0 || (CLIENT_QUERY_ATTRIBUTES && (flags & PARAMETER_COUNT_AVAILABLE)) {
if CLIENT_QUERY_ATTRIBUTES is on {
int<lenenc> parameter_count The number of parameter metadata and values supplied. Overrides the count coming from prepare (num_params) if present.
} – if CLIENT_QUERY_ATTRIBUTES is on
if (parameter_count > 0) {
binary<var> null_bitmap NULL bitmap, length= (paramater_count + 7) / 8
int<1> new_params_bind_flag Flag if parameters must be re-bound
if new_params_bind_flag, for each parameter {
int<2> parameter_type Type of the parameter value. See enum_field_type
if CLIENT_QUERY_ATTRIBUTES is on {
string<lenenc> parameter_name Name of the parameter or empty if not present
} – if CLIENT_QUERY_ATTRIBUTES is on
} – if new_params_bind_flag is on
binary<var> parameter_values value of each parameter
} – if (parameter_count > 0)
} – if (num_params > 0 || (CLIENT_QUERY_ATTRIBUTES && (flags & PARAMETER_COUNT_AVAILABLE))
Example
12 00 00 00 17 01 00 00 00 00 01 00 00 00 00 01 ................
0f 00 03 66 6f 6f ...foo

null_bitmap is like the NULL-bitmap for the Binary Protocol Resultset Row just that it has a bit_offset of 0.

See also
mysql_stmt_execute, cli_stmt_execute, mysql_stmt_precheck, mysqld_stmt_execute