Flink sql查询NULL值错误

[丁浩浩]

Select 
        id,
        name,
        if(type=1,2,null) 
From
        user ;
当我执行上面的sql的时候提示我
[ERROR] Could not execute SQL statement. Reason:
org.apache.calcite.sql.validate.SqlValidatorException: Illegal use of ‘NULL’ 
是无法将null展示吗？