1 var query = from m in ctx.MENU
2     where (m.SUPER_MENU_ID ?? "") == (parentMenuId ?? "")
3     orderby m.SORT_ID descending
4     select new { m.SORT_ID };

 1 SELECT "Project1"."SORT_ID" AS "SORT_ID"
 2    FROM (
 3 
 4 SELECT "Extent1"."SORT_ID" AS "SORT_ID"
 5    FROM "BA"."MENU" "Extent1"
 6  WHERE ((CASE WHEN("Extent1"."SUPER_MENU_ID" IS NULL) THEN ‘‘ 
 7                     ELSE "Extent1"."SUPER_MENU_ID" END) =
 8         (CASE WHEN(&p__linq__0 IS NULL) THEN ‘‘ 
 9                     ELSE &p__linq__0 END))
10 
11 ) "Project1"
12 ORDER BY "Project1"."SORT_ID" DESC

1 parentMenuId = parentMenuId ?? "";
2 var query = from m in ctx.MENU
3       where m.SUPER_MENU_ID == parentMenuId
4     orderby m.SORT_ID descending
5       select new { m.SORT_ID };

1 SELECT "Project1"."SORT_ID" AS "SORT_ID" FROM ( 
2 
3 SELECT "Extent1"."SORT_ID" AS "SORT_ID"
4    FROM "BA"."MENU" "Extent1"
5 WHERE ("Extent1"."SUPER_MENU_ID" = :p__linq__0)
6 
7 ) "Project1"
8 ORDER BY "Project1"."SORT_ID" DESC