CREATE TABLE table_40827 ("AIRLINE" CLOB, "ICAO" CLOB, "IATA" CLOB, "CALLSIGN" CLOB, "COMMENCED OPERATIONS" CLOB)

What is the callsign where the ICAO is AAR?
SELECT "CALLSIGN" FROM table_40827 WHERE "ICAO" = 'aar'
SELECT "CALLSIGN" FROM "table_40827" WHERE "ICAO" = 'aar'