Character conversion in set operations and concatenations

The SQL operations that combine strings include concatenation, set operators, and the IN list of an IN predicate. Within an SQL statement, concatenation combines two or more strings into a new string. Within a fullselect, set operation, or the IN list of an IN predicate combine two or more string columns resulting from the subselects into results column.

All such operations have the following in common:

  • The choice of a result CCSID for the string or column
  • The possible conversion of one or more of the component strings or columns to the result CCSID

For all such operations, the rules for those two actions are the same, as described in Selecting the result CCSID. These rules also apply to the COALESCE scalar function.