For PrestoDB translator, locate(x,y) is translated as strpos(x,y) - i.e. strpos(substring, string), but function has different order of arguments - from PrestoDB documentation - strpos(string, substring)

SELECT StringNum, LOCATE('1', StringNum) FROM BQT1.SmallA

SELECT g_0.stringnum, strpos('1', g_0.stringnum) FROM smalla AS g_0