Hi Ian, Look at it this way: SELECT T1 FROM test2 where ID=3 executed on it's own won't work, since test2 doesn't have a column T1.
You're executing it as a nested statement, and it's using the column T1 from the outer sql statement which is reading from test1 (which does have a column T1). That's why Select * FROM test1 WHERE ID=(SELECT T3 FROM test2 where ID=3); won't work, since T3 isn't defined in test1 or test2. Remember, you can write a statement that says: SELECT 'x' FROM some_table WHERE some_condition 'x' will be returned for every record that matches your condition. Your inner sql statement returns one record for the where condition (because test2 has one record with ID = 3). Thus selecting the outer table's value for T1, which just happens to have the same value as test1's ID column. Essentially, your select statement just says: select * FROM test1 where ID = T1 (as long as your inner statement returns one record) Make sense? -- You received this message because you are subscribed to the Google Groups "H2 Database" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/h2-database?hl=en.
