CASE .. WHEN expression in Oracle SQL

Question

I have the table with 1 column and has following data

Status
a1
i
t
a2
a3

I want to display the following result in my select query

Answer 1

Of course...

select case substr(status,1,1) -- you're only interested in the first character.
            when 'a' then 'Active'
            when 'i' then 'Inactive'
            when 't' then 'Terminated'
       end as statustext
  from stage.tst

However, there's a few worrying things about this schema. Firstly if you have a column that means something, appending a number onto the end it not necessarily the best way to go. Also, depending on the number of status' you have you might want to consider turning this column into a foreign key to a separate table.

---

Based on your comment you definitely want to turn this into a foreign key. For instance

create table statuses ( -- Not a good table name :-)
    status varchar2(10)
  , description varchar2(10)
  , constraint pk_statuses primary key (status)
    )

create table tst (
    id number
  , status varchar2(10)
  , constraint pk_tst primary key (id)
  , constraint fk_tst foreign key (status) references statuses (status)
    )

Your query then becomes

select a.status, b.description
  from tst a
  left outer join statuses b
    on a.status = b.status

Here's a SQL Fiddle to demonstrate.

Answer 2

CASE TO_CHAR(META.RHCONTRATOSFOLHA.CONTRATO)
WHEN '91' AND TO_CHAR(META.RHCONTRATOSFOLHA.UNIDADE) = '0001' THEN '91RJ'
WHEN '91' AND TO_CHAR(META.RHCONTRATOSFOLHA.UNIDADE) = '0002' THEN '91SP'
END CONTRATO,

00905. 00000 -  "missing keyword"
*Cause:    
*Action:
Erro na linha: 15 Coluna: 11

Answer 3

SELECT
  STATUS,
  CASE
    WHEN STATUS IN('a1','a2','a3') 
     THEN 'Active'
    WHEN STATUS = 'i' 
     THEN 'Inactive'
    WHEN STATUS = 't'
     THEN 'Terminated'  ELSE null
  END AS STATUSTEXT
FROM
  stage.tst;

Answer 4

You can rewrite it to use the ELSE condition of a CASE:

SELECT status,
       CASE status
         WHEN 'i' THEN 'Inactive'
         WHEN 't' THEN 'Terminated'
         ELSE 'Active'
       END AS StatusText
FROM   stage.tst 

Answer 5

You can only check the first character of the status. For this you use substring function.

substr(status, 1,1)

In your case past.

Answer 6

Since web search for Oracle case tops to that link, I add here for case statement, though not answer to the question asked about case expression:

CASE
   WHEN grade = 'A' THEN dbms_output.put_line('Excellent');
   WHEN grade = 'B' THEN dbms_output.put_line('Very Good');
   WHEN grade = 'C' THEN dbms_output.put_line('Good');
   WHEN grade = 'D' THEN dbms_output.put_line('Fair');
   WHEN grade = 'F' THEN dbms_output.put_line('Poor');
   ELSE dbms_output.put_line('No such grade');
END CASE;

or other variant:

CASE grade
   WHEN 'A' THEN dbms_output.put_line('Excellent');
   WHEN 'B' THEN dbms_output.put_line('Very Good');
   WHEN 'C' THEN dbms_output.put_line('Good');
   WHEN 'D' THEN dbms_output.put_line('Fair');
   WHEN 'F' THEN dbms_output.put_line('Poor');
   ELSE dbms_output.put_line('No such grade');
END CASE;

Per Oracle docs: https://docs.oracle.com/cd/B10501_01/appdev.920/a96624/04_struc.htm