CREATE TABLE table_204_780 (id NUMBER, "year" NUMBER, "competition" CLOB, "venue" CLOB, "position" CLOB, "notes" CLOB)

what is the difference between notes in 1990 and 1989 ?
SELECT ABS((SELECT "notes" FROM table_204_780 WHERE "year" = 1990) - (SELECT "notes" FROM table_204_780 WHERE "year" = 1989))
SELECT ABS((SELECT "notes" FROM "table_204_780" WHERE "year" = 1990) - (SELECT "notes" FROM "table_204_780" WHERE "year" = 1989))