Problem: I am trying to use a select statement with a UNION clause. A field from one table has no counterpart in the second table and I wish for it to be blank for all rows from the second table. When I try to execute the select statement, I get this error: 'Dynamic SQL Error -SQL error code = -104 -Invalid command -Data type unknown' . What's the correct syntax? Solution: Given the following schema: Create table Employee (First_name Char(15), Last_name Char(25), Title Char(30)); Create table Friends( First_name Char(15), Last_name Char(25), Birth_date Date); and trying to perform this query: Select First_name, Last_name, Title from Employee UNION Select First_name, Last_name, ' ' as Title from Friends gives this error: Dynamic SQL Error -SQL error code = -104 -Invalid command -Data type unknown The solution is to cast the values so that the datatypes in both sub-selects match. Here's the corrected version of the query: Select First_name, Last_name, Title from Employee UNION Select First_name, Last_name, Cast(' ' as Char(30)) as Title from Friends
Last Modified: 29-SEP-00