How to replace a comma separated value in table column with user input value oracle

delete from yourtable t
where
  instr(','||t.col||',', '123') > 0

You can replace '123' with a parameter if you like.

But a better way would be not to store comma separated values, and create a detail table instead. If you need to look for a specific value within a comma separated list, you cannot make use of indices, amongst other limitations.

[edit] Misunderstood the question. You meant this:

update YourTable t
set
  t.col = substr(substr(replace(','||t.col||',', ',123,', ','), 2), -2)
where
  instr(','||t.col||',', '123') > 0

• Add ',' before and after to match items at the beginning or end of the value.
• Replace using the value ',123,' (within comma's) to prevent accidentally matching 1234 too.
• Use substr twice to remove the first and last character (the added commas)
• Use instr in the where to prevent updating records that don't need to be updated (better performance).

try this :

UPDATE t
SET col = REPLACE(REPLACE(col, '&variable', ''), ',', '') FROM t ;