CASE SQL Oracle查询-有什么问题？

Question

I have following query to select the view to be used in the query, however I get the error:

FROM keyword not found where expected

select *, (CASE WHEN 'employee' = 'employee' THEN employee ELSE vw END) FROM type1

Answer 1

You cannot use * and individual columns together in select statement.

SELECT  (CASE WHEN 'employee' = 'employee' THEN 'employee' ELSE 'vw' END)
  FROM  dual

Answer 2

select type1.*,
      (CASE WHEN 'employee' = 'employee'
            THEN employee 
            ELSE vw 
       END)
FROM type1

I always prefix with the tablename/table alias to the * and it works!!

We just need to specify, fetch all the column from this table, when we specify combination of wildcard and other select expressions!

Answer 3

You cant do a *, in Oracle without an alias/TableName(.) in front of it. List out the columns you want to see in the result set or add a table alias/tablename.

Answer 4

您不能设置选择语句应从语句的列列表部分中检索数据的视图的名称。