How do you select all columns, plus the result of a CASE statement in oracle 11g?

问题

I want to select *, and not have to type out all individual columns, but I also want to include a custom column with a case statement. I tried the following:

select *, (case when PRI_VAL = 1 then 'High'
                when PRI_VAL = 2 then 'Med'
                when PRI_VAL = 3 then 'Low'
          end) as PRIORITY
from MYTABLE;

But it is complaining that

ORA-00923: FROM keyword not found where expected

回答1:

Add an alias for mytable like this:

select t.*, (case when PRI_VAL = 1 then 'High'
                when PRI_VAL = 2 then 'Med'
                when PRI_VAL = 3 then 'Low'
          end) as PRIORITY
from MYTABLE t;

This is not dependent on any specific Oracle version, not sure about other databases.

回答2:

As IronGoofy says, add the table alias.

On a different note be aware that there is a handy searched case syntax that would be suitable for your situation:

select t.*,
       case PRI_VAL
         when 1 then 'High' 
         when 2 then 'Med' 
         when 3 then 'Low' 
       end as PRIORITY 
from MYTABLE t; 

回答3:

Do it like this:

select e.*,
case deptno
when 30 then 'High'
when 20 then 'Medi'
when 10 then 'Low'
else 'Very Low'
end case
from emp e order by deptno desc;

来源：https://stackoverflow.com/questions/1751856/how-do-you-select-all-columns-plus-the-result-of-a-case-statement-in-oracle-11g