¿Hay alguna función agregada de MySQL para CONTAINS?

La forma correcta de hacerlo:

SELECT
   user,
   IF(SUM(group = 'A'), TRUE, FALSE) AS IN_A,
   IF(SUM(group = 'B'), TRUE, FALSE) AS IN_B,
   IF(SUM(group = 'C'), TRUE, FALSE) AS IN_C
FROM users
GROUP BY user