Oracle 18c

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CREATE TABLE my_table ( my_col ) AS
SELECT 'something' FROM DUAL UNION ALL
SELECT 'nothing' FROM DUAL UNION ALL
SELECT 'something and another thing' FROM DUAL UNION ALL
SELECT 'this something and that thing' FROM DUAL;
4 rows affected

SELECT *
FROM   my_table
WHERE  CASE WHEN my_col LIKE '%something%' THEN 'Y' ELSE 'N' END = 'Y';

MY_COL

something

something and another thing

this something and that thing

SELECT *
FROM   my_table
WHERE  DECODE( INSTR( my_col, 'something' ), 0, 'N', 'Y' ) = 'Y';

MY_COL

something

something and another thing

this something and that thing

SELECT *
FROM   my_table
WHERE  my_col LIKE '%something%';

MY_COL

something

something and another thing

this something and that thing

SELECT *
FROM   my_table
WHERE  INSTR( my_col, 'something' ) > 0;

MY_COL

something

something and another thing

this something and that thing

SELECT *
FROM   my_table
WHERE  REGEXP_LIKE( my_col, 'something' );

MY_COL

something

something and another thing

this something and that thing