mysql alter小结

设置字符集编码

##设置utf8
ALTER TABLE user_pdf CHANGE title title VARCHAR (255) CHARACTER
SET utf8 COLLATE utf8_general_ci NOT NULL DEFAULT '' COMMENT '标题',ALGORITHM=inplace,LOCK=NONE;

##设置utf8mb4
ALTER TABLE user_pdf CHANGE title title VARCHAR (255) CHARACTER
SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL DEFAULT '' COMMENT '标题',ALGORITHM=inplace,LOCK=NONE;