In 4D, the SQL engine does not allow athrimetic calculations between two time types.

For the following table:


The following code will generate an error

ARRAY TIME(Times;0) Begin SQL    SELECT (Tend-Tstart)    FROM TimeTest    Into :Times End SQL

To work around this a simple method can be created and ran inside the SQL Statment.

// Util_SQL_TIMEDIFF // // Desription: // Used For SQL calculation of Diffiference between two times // // Parameters: // $1: End Time (Larger Value of the Two) // $2: Start Time (Lesser Value of the Two) // Result: // $0: Time difference between end and start times // ---------------------------------------------------- C_TIME($1;$end_t) C_TIME($2;$start_t) C_TIME($0;$dif_t) If (Count parameters=2)    $end_t:=$1    $start_t:=$2    $dif_t:=$end_t-$start_t    $0:=$dif_t End if

The "Available through 4D Mobile call" Method Properrty must be toggled on:


Then the method can be used in the SQL statement as follows:

ARRAY TIME(Times;0) Begin SQL    SELECT {FN Util_SQL_TIMEDIFF(Tend,Tstart) AS DURATION}    FROM TimeTest    Into :Times End SQL