How do I print the matched pattern that produced the result of a multi-like case statement?

Question

I am looking to store in a column (matched_pattern), as a string value, the matched pattern for a string field (title) from a multi-like case when statement in SQL.

Example table:

|      Title          |     Email        |
|---------------------|------------------|
|         CEO         | [email protected]   |
|---------------------|------------------|
|         COO         | [email protected]  |
|---------------------|------------------| 

The query I have is

select 
title,
email,
CASE WHEN lower(title) LIKE     '%cco%' OR
lower(title) LIKE '%ceo%' THEN 'CxO' ELSE null END persona
FROM table

The result I want is

|      Title |     Email        | Persona |matched_pattern  |
|------------|------------------|---------------------------|
|  CEO       | [email protected]   | CxO     | '%ceo%'         |
|------------|------------------|---------|-----------------|
|  CcO       | [email protected]  | CxO     | '%cco%'         |
|------------|------------------|---------|-----------------|

Is there a way of storing the code that generates the result in a separate column? I have used another case statement to create the matched_pattern column

SELECT
title,
CASE WHEN lower(title) LIKE     '%cco%' THEN 'CxO'
CASE WHEN lower(title) LIKE     '%ceo%' THEN 'CxO'
ELSE null END persona,
CASE WHEN lower(title) LIKE     '%cco%' THEN '%cco%'
CASE WHEN lower(title) LIKE     '%ceo%' THEN '%ceo%'
ELSE null END matched_pattern
FROM table

Is there a better way to do this?

Answer 1

If you materialize the patterns in another table or temp table or something, you can simply do this:

SELECT *
FROM DataSource DS
LEFT JOIN Paterns P 
    ON DS.[Title] LIKE P.[patern]

Here is full working example on SQL Server:

CREATE TABLE DataSource
(
    [Title] VARCHAR(12)
   ,[Email] VARCHAR(32)
);

CREATE TABLE Paterns
(
    [patern] VARCHAR(12)
   ,[value] VARCHAR(12)
);

GO

INSERT INTO DataSource ([Title], [Email])
VALUES ('CEO', '[email protected]')
      ,('CEO', '[email protected]');

INSERT INTO Paterns ([patern], [value])
VALUES ('%ceo%', 'CxO')
      ,('%cco%', 'CxO')


SELECT *
FROM DataSource DS
LEFT JOIN Paterns P 
    ON DS.[Title] LIKE P.[patern]