This section demonstrates techniques for finding the minimum and maximum values from the same table.
Note the use of two separate COMPUTE commands. Example 2 runs faster because R:BASE allows both COMPUTEs to be executed in one command. Example 3 is the fastest because it uses the SELECT INTO varlist command.
SET VAR t1 TIME = NULL
SET VAR t2 TIME = NULL
SET VAR vDiff INTEGER = NULL
--Example 1 - Slow
SET VAR t1 = (.#TIME)
SET VAR vMin INTEGER
SET VAR vMax INTEGER
COMPUTE vMin AS MIN Altitude FROM Airports
COMPUTE vMax AS MAX Altitude FROM Airports
SET VAR t2 = (.#TIME)
SET VAR vDiff = (.t2 - .t1)
PAUSE 2 USING .vDiff
--Example 2 - Faster
SET VAR t1 = (.#TIME)
SET VAR vMin INTEGER
SET VAR vMax INTEGER
COMPUTE vMin AS MIN Altitude, vMax AS MAX Altitude +
FROM Airports
SET VAR t2 = (.#TIME)
SET VAR vDiff = (.t2 - .t1)
SET VAR vTime = (RTIME(0,0,.vDiff))
PAUSE 2 USING .vTime
--Example 3 - Fastest
SET VAR t1 = (.#TIME)
SET VAR vMin INTEGER
SET VAR vMax INTEGER
SELECT MIN (Altitude), MAX (Altitude) INTO vMin, vMax +
FROM Airports
SET VAR t2 = (.#TIME)
SET VAR vDiff = (.t2 - .t1)
SET VAR vTime = (RTIME(0,0,.vDiff))
PAUSE 2 USING .vTime
