Column aliasing in SELECT statements doesn't work with SQuirrel SQL + Firebird

问题

I tried add an column alias in SELECT statement using SQuirrel SQL 3.4 + Firebird 1.5 + Driver JDBC Jaybird 2.2.[0|1] (JVM 1.7.0_03), but doesn't work. The column aliased appears with the original name of column. In another tool (DBExpert) the same statement works fine.

Statement: SELECT column1 AS alias1, column2 FROM table;
Resultant columns name in SquirrelSQL: column1 - column2
Resultant columns name in DBExpert: alias1 - column2

Tried add ' and " around alias name, but also not work.

Someone have an idea?

Edit: I updated the JDBC Jaybird driver to 2.2.1 version (released Sept/30) and the problem remains.

Edit 2: Problem fixed!

The problenm is caused by default preferences of Squirrel SQL.

To fix it, go to "File" -> "Global Preferences", in tab "Data Type Controls" find "General (applies to all types)" and mark the combo-box "Use column labels instead of column names in result headers".

See the screenshot: http://i1-win.softpedia-static.com/screenshots/SQuirrel-SQL-Client_4.png?1345342622

Enjoy.

回答1:

The problem is due to confusion in the JDBC specs (at least historically) and a change in Jaybird with regard to what it reports as columnNames and columnLabels in the resultset metadata. As far as I am aware in JDBC 2.0 and earlier, the distinction between columnName and columnLabel was not well defined, so in almost all cases getColumnName() returned the same value as getColumnLabel() (ie the AS alias if specified).

With JDBC 3.0 a sharper distinction was made: the columnName was to be the name of the underlying column in a table (if any), the columnLabel is the AS-alias if specified and otherwise the columnName. Jaybird 2.1.6 and earlier used to return the same value for getColumnLabel() and getColumnName() (ie the columnLabel), this was changed in Jaybird 2.2.

Apparently Squirrel defaults to the non-JDBC compliant option of columnName, instead of columnLabel. As you already found out: there is an option to get it to use the columnLabel instead. The other option you have is to use Jaybird 2.2.1 or higher and add the connection property columnLabelForName=true.