Impermissible Client Character Sets Some character sets cannot be used as the client character set. See Impermissible Client Character Sets. To determine this, the server uses the  character_set_connection  and  collation_connection system variables: The  character_set_results  system variable indicates the character set in which the server returns query results to the client. This includes result data such as column values, result metadata such as column names, and error messages. To tell the server to perform no conversion of result sets or error messages, set character_set_results  to  NULL  or  binary : SET character_set_results = NULL; SET character_set_results = binary; For more information about character sets and error messages, see Section 10.6, “Error Message Character Set” . To see the values of the character set and collation system variables that apply to the current session, use this statement: The following simpler statements also display the connection variables, but include other related variables as well. They can be useful to see  all  character set and collation system variables: SHOW SESSION VARIABLES LIKE ’character\_set\_%’; SHOW SESSION VARIABLES LIKE ’collation\_%’; Clients can fine-tune the settings for these variables, or depend on the defaults (in which case, you can skip the rest of this section). If you do not use the defaults, you must change the character settings  for each connection to the server. The  character_set_client  system variable cannot be set to certain character sets: 1944 Impermissible Client Character Sets Note •What character set should the server translate statements to after receiving them? •The server converts statements sent by the client from  character_set_client  to character_set_connection . Exception: For string literals that have an introducer such as _utf8mb4  or  _latin2 , the introducer determines the character set. See Section 10.3.8, “Character Set Introducers” . • collation_connection  is important for comparisons of literal strings. For comparisons of strings with column values,  collation_connection  does not matter because columns have their own collation, which has a higher collation precedence (see Section 10.8.4, “Collation Coercibility in Expressions” ). •What character set should the server translate query results to before shipping them back to the client? SELECT * FROM performance_schema.session_variables WHERE VARIABLE_NAME IN ( ’character_set_client’, ’character_set_connection’, ’character_set_results’, ’collation_connection’ ) ORDER BY VARIABLE_NAME;