There are three or four cases in transformSortClause() and I had fixed
only one case for UNION. A second case is now fixed, in the same way; I
assigned INT4OID to the column type for the "won't actually happen"
sort. Didn't want to skip the code entirely, since the backend needs to
_try_ a sort to get the NULLs right. I'm not certain under what
circumstances the other cases are invoked and these are not yet
fixed up, though perhaps they don't need to be...
Used in the generic "CREATE xxx" parsing.
Do some automatic type conversion for inserts from other columns.
Previous trouble with "resjunk" regression test remains for now.
Currently force the type to match the _first_ select in the union.
Move oper_select_candidate() from parse_func.c to parse_oper.c.
Throw error inside of oper_inexact() if no match for binary operators.
Check more carefully that types can be coerced
even if there is only one candidate operator in oper_inexact().
Fix up error messages for more uniform look.
Remove unused code.
Fix up comments.
