pears.PersonAvailableAtTime

CREATE FUNCTION "pears"."PersonAvailableAtTime"( 
  /* Application Maintained Function / Procedure - DO NOT EDIT*/
  IN "sPersonid" CHAR(20),IN "dShiftDate" DATE,IN "tShiftFrom" TIME,IN "tShiftTo" TIME,IN "iCheckExplicitlyAvailable" SMALLINT ) 
RETURNS CHAR(1)
BEGIN
  DECLARE "foundState" CHAR(1);
  SET "foundstate" = NULL; -- If we return null, we have found no explicit unavailability or availability
  -- First check for all day unavailability
  SELECT FIRST "state" INTO "foundstate" FROM "tempshift" WHERE "state" NOT IN( 'A','C' ) 
    AND "personid" = "spersonid" AND "shiftdate" = "dshiftdate" AND("timefrom" IS NULL OR "timeto" IS NULL);
  IF "foundstate" IS NULL THEN -- Look for non-concurrent employments
    SELECT FIRST 'W' INTO "foundstate" FROM "employment"
      WHERE "isnull"("concurrent",0) = 0 AND "personid" = "spersonid" AND "startdate" <= "dshiftdate" AND("leavedate" IS NULL OR "leavedate" >= "dshiftdate")
  END IF;
  IF "foundstate" IS NULL THEN
    SET "foundstate" = "personavailableforplaniterate"("spersonid","dshiftdate","tshiftfrom","tshiftto","icheckexplicitlyavailable",'')
  END IF;
  RETURN "foundstate"
END