语法: if(boolean testCondition, T valueTrue, T valueFalseOrNull)
说明: 当条件testCondition为TRUE时,返回valueTrue;否则返回valueFalseOrNull
举例:
mysql
select source,if(source='猎聘',1,2) as flag from t_cal_dowell_resume
hive:
select a,b,c,if(b='上帝',1,2) as bb from tmp.csv_t1