Display labels

You can assign a display label to a computed or derived data column to replace the default column header expression. In Query, Query, and Query, the derived data appears in the expression column. The following query also presents derived values, but the column that displays the derived values has the descriptive header taxed.
Figure 1: Query
SELECT stock_num, description, unit_price, 
       unit_price * 1.07 taxed
   FROM stock
   WHERE unit_price >= 400;
The result shows that the label taxed is assigned to the expression in the projection list that displays the results of the operation unit_price * 1.07.
Figure 2: Query result
stock_num description     unit_price            taxed
       
        1 baseball gloves    $800.00          $856.00
        1 baseball gloves    $450.00          $481.50
        4 football           $960.00         $1027.20
        4 football           $480.00          $513.60
        7 basketball         $600.00          $642.00
        8 volleyball         $840.00          $898.80
      102 bicycle brakes     $480.00          $513.60
      111 10-spd, assmbld    $499.99          $534.99
      112 12-spd, assmbld    $549.00          $587.43
      113 18-spd, assmbld    $685.90          $733.91
      203 irons/wedge        $670.00          $716.90
In the following query, the label surcharge is defined for the column that displays the results of the operation total_price + 6.50.
Figure 3: Query
SELECT item_num, order_num, quantity,
       total_price, total_price + 6.50 surcharge
   FROM items
   WHERE quantity < 5;
The surcharge column is labeled in the output.
Figure 4: Query result
item_num   order_num quantity total_price    surcharge 

       1        1001        1     $250.00       $256.50 
       1        1002        1     $960.00       $966.50
       2        1002        1     $240.00       $246.50
       1        1003        1      $20.00        $26.50
       2        1003        1     $840.00       $846.50

       1        1023        2      $40.00        $46.50
       2        1023        2     $116.00       $122.50
       3        1023        1      $80.00        $86.50
       4        1023        1     $228.00       $234.50
       5        1023        1     $170.00       $176.50
       6        1023        1     $190.00       $196.50
The following query assigns the label span to the column that displays the results of subtracting the DATETIME column call_dtime from the DATETIME column res_dtime.
Figure 5: Query
SELECT customer_num, call_code, call_dtime, 
       res_dtime - call_dtime span
   FROM cust_calls
   ORDER BY customer_num;
The span column is labeled in the output.
Figure 6: Query result
customer_num call_code call_dtime               span
       
         106 D         1998-06-12 08:20         0 00:05 
         110 L         1998-07-07 10:24         0 00:06
         116 I         1997-11-28 13:34         0 03:13
         116 I         1997-12-21 11:24         5 20:55
         119 B         1998-07-01 15:00         0 17:21
         121 O         1998-07-10 14:05         0 00:01
         127 I         1998-07-31 14:30