SQL The column 'Id' was specified multiple

问题:

Possible Duplicate:
sql 2005 - The column was specified multiple times

  SELECT TOP(20) * 
    FROM (SELECT * 
            FROM [3D_Benchmarks] 
            JOIN [3D_Slugs] ON [3D_Benchmarks].Id = [3D_Slugs].BenchmarkId) AS tb 
ORDER BY tb.FPS DESC;

I Get This Error:

The column 'Id' was specified multiple times for 'tb'.

回答1:

Instead of select * use select table.columnname or tablename.*.

回答2:

SELECT * 
            FROM [3D_Benchmarks] 
            JOIN [3D_Slugs] ON [3D_Benchmarks].Id = [3D_Slugs].BenchmarkId) AS tb

3D_Benchmarks have id column,3D_Slugs have id column too.

for explame:[3D_Benchmarks].id as aid,3D_Slugs.id as bid