CONCAT_WS

Joins strings, inserting the given separator between them.

MySQL 8.4

CONCAT_WS(separator, str[, ...])

Return value

A string; NULL arguments are skipped, but a NULL separator gives NULL

MySQL 8.4

SELECT CONCAT_WS('-', '2024', '03', '08');

CONCAT_WS('-', '2024', '03', '08')
2024-03-08

MySQL 8.4

SELECT CONCAT_WS(' ', last_name, first_name, middle_name) AS full_name
FROM Teacher;

full_name
Romashkin Pavel Petrovich
Kolesnikov Vasilij Antonovich
Vaulina Mariya Stepanovna
ZHedrinskaya Taisiya Timurovna
Sosnovskaya Marina Gennadevna
Myasoedova Ekaterina YAkovlevna
Arakcheeva Liliya Timurovna
Krauze Sofya Dmitrievna
Ostrozhskaya Viktoriya Nikolaevna
Krylov YUrij

Unlike CONCAT, CONCAT_WS skips NULL arguments instead of returning NULL.

Empty strings are not skipped, and the separator is placed around them too: CONCAT_WS('-', 'a', '', 'b') returns a--b.