In an INSERT statement with a QUERY expression or in an UPDATE statement, the attempt was made to assign a character string to a column of data type CHAR. This character string was too long. The error message is returned for the first occurring value with an exceeding length, not while analyzing the maximum column lengths.
You can determine rows with an exceeding length by means of SELECT... WHERE LENGTH (<column name>) > <unsigned_integer>. You can increase the length of the corresponding column by means of an ALTER TABLE statement.