Error "1660 Illegal value used as argument of dynamic column function" is not helpful

[Philip Stoev]

Error " 1660 Illegal value used as argument of dynamic column function" shows up when one tries to assign two values to the same dynamic column within a single statement. The same operation would be allowed in an INSERT, where the last value would be used. So, either make dynamic columns behave as INSERT, or provide a better error message, e.g. "duplicate field name"

For example:

 SELECT COLUMN_CREATE( 5 , 1 , 5 , 1 ) ;

[Michael Widenius (monty)]

This is a restriction of the current implementation. I will for now document this in the manual.
The idea is that in the future it will behave as INSERT in this case.

[Michael Widenius (monty)]

For now, you can only get the error: "Illegal value used as argument of dynamic column function" if you provide a too big column number (> 65535) or if you have the same column number twice in a COLUMN_CREATE or COLUM_ADD function.