Column Labels

 You might have noticed the text that appears at the top of each column in the SELECT output--the column label. The label usually is the name of the selected column. However, you can control the text that appears at the top of each column by using the AS keyword. For example, Figure  replaces the default column label firstname with the column label buddy.  

        test=> SELECT firstname AS buddy FROM friend ORDER BY buddy;
              buddy      
        -----------------
         Cindy          
         Jack           
         Mark           
         Mike           
         Sam            
        (5 rows)  

You might have noticed that the query in Figure  on page  has the column label ?column?. The database server returns this label when there is no suitable label. In that case, the result of an addition does not have an appropriate label. Figure  shows the same query with an appropriate label added using AS.   

        test=> SELECT 1 + 3 AS total;
         total 
        -------
             4
        (1 row)