SQLite 3.39

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CREATE TABLE tablename (`code` TEXT);
✓
INSERT INTO tablename (`code`) VALUES
  ('9897.1t'),
  ('gb5ffh-hy'),
  ('dhy4.dt4-kj'),
  ('abx');
✓
WITH cte(char) AS (VALUES ('.'), ('-')) -- you can add more chars in the list
SELECT code,
       SUBSTR(t.code, 1, COALESCE(MIN(INSTR(t.code, c.char)) - 1, LENGTH(t.code))) new_code
FROM tablename t LEFT JOIN cte c
ON INSTR(t.code, c.char)
GROUP BY t.code;


code
new_code


9897.1t
9897

abx
abx

dhy4.dt4-kj
dhy4

gb5ffh-hy
gb5ffh

`code`	`new_code`
`9897.1t`	`9897`
`abx`	`abx`
`dhy4.dt4-kj`	`dhy4`
`gb5ffh-hy`	`gb5ffh`