CREATE TABLE table_203_538 (id NUMBER, "flight" CLOB, "date" CLOB, "payload nickname" CLOB, "payload" CLOB, "orbit" CLOB, "result" CLOB)

how many years passed between flight tf2 and flight f8 ?
SELECT ABS((SELECT "date" FROM table_203_538 WHERE "flight" = 'tf2') - (SELECT "date" FROM table_203_538 WHERE "flight" = 'f8'))
SELECT ABS((SELECT "date" FROM "table_203_538" WHERE "flight" = 'tf2') - (SELECT "date" FROM "table_203_538" WHERE "flight" = 'f8'))