How to replace a string with a specific value directly in SQL SELECT query (Oracle)

Question

I have a table with employee data inside:

+----+-------+----------+------------+
| ID | Name  | LastName | Salutation |
+----+-------+----------+------------+
|  1 | John  | Doe      | Mr         |
|  2 | Alice | Smith    | Ms         |
+----+-------+----------+------------+

I want to select some of that data but I want to replace Mr with 1 and Ms with 2 using the SQL query itself.

I have tried to use REGEXP_REPLACE what actually did work for one of the salutations:

SELECT ID, Name, LastName, REGEXP_REPLACE(Salutation, 'Mr', '1') FROM employees

It gave me a following result:

+----+-------+----------+------------+
| ID | Name  | LastName | Salutation |
+----+-------+----------+------------+
|  1 | John  | Doe      | 1          |
|  2 | Alice | Smith    | Ms         |
|  3 | John  | Smith    | 1          |
|  4 | Alice | Doe      | Ms         |
+----+-------+----------+------------+

How can I replace also Ms to 2 ?

Answer 1

You can use the decode

select ID, Name, LastName.
    DECODE(Salutation,'Mr',1,2) as Salutation
from employee

Answer 2

You can achieve it by using case statement. Here is the DEMO

select
    ID,
    Name,
    LastName,
    (case when Salutation = 'Mr' then 1  else 2 end) as Salutation
from employee
order by
    ID

Answer 3

SELECT
    ID, Name, LastName,
    REPLACE(TMP_TABLE.TMP_Salutation, 'Ms', '2')
FROM (
    SELECT
    REPLACE(Salutation, 'Mr', '1') TMP_Salutation
    FROM employees
) TMP_TABLE;

This code will first replace all occurances of 'Mr' with '1' in the subquery and return a table which we gave an alias of 'TMP_TABLE'. Then, all the occurances of 'Ms' in that 'TMP_TABLE' will be replaced with '2'