CREATE TABLE table_20562 ("Code" TEXT, "District" TEXT, "Headquarters" TEXT, "Population  ( 2011 ) " FLOAT, "Area  ( km\\u00b2 ) " FLOAT, "Density  ( /km\\u00b2 ) " FLOAT, "Official website" TEXT)

What is the abbreviation of the district of Mahbubnagar?
SELECT "Code" FROM table_20562 WHERE "District" = 'Mahbubnagar'
SELECT "Code" FROM "table_20562" WHERE "District" = 'Mahbubnagar'