This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
Say I have two tables: user_field_data, containing user_id, field_1, field_2, field_... user_field_meta, containing field_id, field_title So whatever has a field_id of 1 in the meta table corresponds to the field_1 column in the data table. If I was building the query in java, it'd be something like...
My question is, is there a way to do this in one SQL SELECT statement? Ie, have sql dynamically build a column name?
I don't believe that you can do this with a prepared statement. The table names and column names can't be parameters. If you think about it, the purpose of using prepared statements is to create a pre-compiled SQL once that can be used many time. If you used a table name or column name in the SQL, the database engine would have to validate the SQL every time you use it to make sure the table and/or column name is valid. And that's essentially what happens when you use a statement. So you have a couple of choices. Option 1: use a (regular) statement
Option 2: use a prepared statement
In the second example the query returns every column, but you pull out only the one you want. [ March 29, 2004: Message edited by: Wayne L Johnson ]