The Ultimate Guide to High Availability with MariaDB

COM_QUERY

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With the COM_QUERY command, the client sends the server an SQL statement to be executed immediately.

Fields



SQL statement should be properly escaped. Escape character is usually backslash '\' = 0x5c. However , if status flag returned by the last OK Packet had NO_BACKSLASH_ESCAPES bit set, then the escape character is single quote(' = 0x60)

if escape character is backslash, the following characters are escaped:

  • single quote (' = 0x60)
  • back slash (\ = 0x5c)
  • double quote (" = 0x22)
  • null character (0x00)

If escape character is single quote, only single quote (' = 0x60) can be escaped.

Response

The server can answer with 4 different responses that can be differentiated by the first byte (packet header):

  • 0xFF - ERR_Packet if any error occurs.
  • 0x00 - OK_Packet when query execution works without resultset.
  • 0xFB - LOCAL_INFILE Packet if query was "LOCAL INFILE ...".
  • Or a Resultset, when query returns results (in case of SELECT query for example).

Example

1b 00 00 00 03 44 52 4f 50 20 54 41 42 4c 45 20.....DROP TABLE
49 46 20 45 58 49 53 54 53 20 62 75 6c 6b 31IF EXISTS bulk1

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