CREATE TABLE table_train_30 ("id" NUMBER, "serum_potassium" FLOAT, "hyperkalemia" BOOLEAN, "renal_disease" BOOLEAN, "cardiopulmonary_resuscitation" BOOLEAN, "receiving_vasopressor" BOOLEAN, "age" FLOAT, "NOUSE" FLOAT)

age < 18 years;
SELECT * FROM table_train_30 WHERE age < 18
SELECT * FROM "table_train_30" WHERE "age" < 18