MySQL函數GROUP_CONCAT

關於mysql函數GROUP_CONCAT

GROUP_CONCAT()是MySQL資料庫提供的一個函數，通常跟GROUP BY一起用,具體可參考MySQL官方文檔:http://dev.mysql.com/doc/refman/5.0/en/group-by-functions.html#function_group-concat 。

GROUP_CONCAT( [ DISTINCT ] expr [ ,expr ... ] [ ORDER BY { unsigned_integer | col_name | expr} [ ASC | DESC ] [ ,col_name ...] ] [ SEPARATOR str_val] )

SELECT student_id, GROUP_CONCAT( courses_id) AS courses FROM student_courses WHERE student_id=2 GROUP BY student_id;

"SELECT student_id, GROUP_CONCAT(courses_id) AS courses FROM student_courses WHERE student_id=2 GROUP BY student_id"

SELECT student_id, GROUP_CONCAT( courses_id SEPARATOR '|||' )  AS courses FROM student_courses WHERE student_id=2 GROUP BY  student_id;

SELECT student_id, GROUP_CONCAT( courses_id ORDER BY courses_id DESC) AS courses FROM student_courses WHERE student_id=2 GROUP BY student_id;