— This shows you all the indexes. Look for duplicates like fk_user_id_1, fk_user_id_2
SHOW INDEX FROM shifts;

— Then delete the duplicates one by one
ALTER TABLE shifts DROP INDEX index_name_here;

— Clean up redundant indexes on ‘departments’
ALTER TABLE departments
DROP INDEX name_2, DROP INDEX name_3, DROP INDEX name_4, DROP INDEX name_5,
DROP INDEX name_6, DROP INDEX name_7, DROP INDEX name_8, DROP INDEX name_9,
DROP INDEX name_10, DROP INDEX name_11, DROP INDEX name_12, DROP INDEX name_13,
DROP INDEX name_14, DROP INDEX name_15, DROP INDEX name_16, DROP INDEX name_17,
DROP INDEX name_18, DROP INDEX name_19, DROP INDEX name_20, DROP INDEX name_21,
DROP INDEX name_22, DROP INDEX name_23, DROP INDEX name_24, DROP INDEX name_25,
DROP INDEX name_26, DROP INDEX name_27, DROP INDEX name_28, DROP INDEX name_29,
DROP INDEX name_30, DROP INDEX name_31, DROP INDEX name_32, DROP INDEX name_33,
DROP INDEX name_34, DROP INDEX name_35, DROP INDEX name_36, DROP INDEX name_37,
DROP INDEX name_38, DROP INDEX name_39, DROP INDEX name_40, DROP INDEX name_41,
DROP INDEX name_42, DROP INDEX name_43, DROP INDEX name_44, DROP INDEX name_45,
DROP INDEX name_46, DROP INDEX name_47, DROP INDEX name_48, DROP INDEX name_49,
DROP INDEX name_50, DROP INDEX name_51, DROP INDEX name_52, DROP INDEX name_53,
DROP INDEX name_54, DROP INDEX name_55, DROP INDEX name_56, DROP INDEX name_57,
DROP INDEX name_58, DROP INDEX name_59, DROP INDEX name_60, DROP INDEX name_61,
DROP INDEX name_62, DROP INDEX name_63;