Error: "Firebird Database Error 335544396: column is not defined in table" When Connecting to Firebird

Published: 27 Apr 2017
Last Modified Date: 28 Apr 2017


When connecting to Firebird using custom SQL, the following error might occur:

"Firebird Database Error 335544396 "column is not defined in table"


  • Tableau Desktop
  • Firebird


  • Review the fields that the custom SQL is bringing in to make sure any of them are not a BLOB field, or any other unsupported data types.
  • If the field needs to be brought into Tableau Desktop:
    • Adjust the custom SQL using a CAST() statement to change the BLOB into a string.
      • From :

        DECLARE VARIABLE c1 VARCHAR(32000); 
        SELECT SUBSTRING(blob1 FROM 1 FOR 32000) FROM t1 INTO c1;
      • Custom SQL is not typically something we can edit, and the format may change depending on the DB (if it is not Firebird)
    • Change the BLOB into a string within the database itself.


Tableau Desktop has found an unsupported data type in the custom SQL and is unable to bring in data as a result.
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