【1】反引号`，数字1左边的符号。tab键上面的符号。
它是为了区分MYSQL的保留字与普通字符而引入的符号。
不加反引号建的表不能包含MYSQL保留字，否则出错
如上图，很明显的，如果我们直接建立名称为select的表，会报错。如果我们加上反引号``就创建成功了。
核心原因是因为，当我们没加反引号的时候，select 默认是 Mysql的关键字，所以报错了。
加了反引号`` 之后，Mysql就把它识别成了一个常规字符串。
反引号`，数字1左边的符号。tab键上面的符号。
【2】保留字不能用于表名
比如desc，此时需要加入反引号来区别，但使用表名时可忽略反引号。
create temporary table desc 报错 create temporary table `desc` 成功
【3】保留字也不能用于字段名
，比如desc，此时也需要加入反引号，并且insert等使用时也要加上反引号。
-- 这里就不贴图了，一个意思，只是由表名换成了列名
create table `test`（`desc` varchar(255)）成功 insert into test(desc) values('fxf')失败 insert into test(`desc`) values('fxf')成功
【4】保留字参考列表
从网上找了一个mysql的保留字列表，仅供参考。
| ADD | ALL | ALTER |
| ANALYZE | AND | AS |
| ASC | ASENSITIVE | BEFORE |
| BETWEEN | BIGINT | BINARY |
| BLOB | BOTH | BY |
| CALL | CASCADE | CASE |
| CHANGE | CHAR | CHARACTER |
| CHECK | COLLATE | COLUMN |
| CONDITION | CONNECTION | CONSTRAINT |
| CONTINUE | CONVERT | CREATE |
| CROSS | CURRENT_DATE | CURRENT_TIME |
| CURRENT_TIMESTAMP | CURRENT_USER | CURSOR |
| DATABASE | DATABASES | DAY_HOUR |
| DAY_MICROSECOND | DAY_MINUTE | DAY_SECOND |
| DEC | DECIMAL | DECLARE |
| DEFAULT | DELAYED | DELETE |
| DESC | DESCRIBE | DETERMINISTIC |
| DISTINCT | DISTINCTROW | DIV |
| DOUBLE | DROP | DUAL |
| EACH | ELSE | ELSEIF |
| ENCLOSED | ESCAPED | EXISTS |
| EXIT | EXPLAIN | FALSE |
| FETCH | FLOAT | FLOAT4 |
| FLOAT8 | FOR | FORCE |
| FOREIGN | FROM | FULLTEXT |
| GOTO | GRANT | GROUP |
| HAVING | HIGH_PRIORITY | HOUR_MICROSECOND |
| HOUR_MINUTE | HOUR_SECOND | IF |
| IGNORE | IN | INDEX |
| INFILE | INNER | INOUT |
| INSENSITIVE | INSERT | INT |
| INT1 | INT2 | INT3 |
| INT4 | INT8 | INTEGER |
| INTERVAL | INTO | IS |
| ITERATE | JOIN | KEY |
| KEYS | KILL | LABEL |
| LEADING | LEAVE | LEFT |
| LIKE | LIMIT | LINEAR |
| LINES | LOAD | LOCALTIME |
| LOCALTIMESTAMP | LOCK | LONG |
| LONGBLOB | LONGTEXT | LOOP |
| LOW_PRIORITY | MATCH | MEDIUMBLOB |
| MEDIUMINT | MEDIUMTEXT | MIDDLEINT |
| MINUTE_MICROSECOND | MINUTE_SECOND | MOD |
| MODIFIES | NATURAL | NOT |
| NO_WRITE_TO_BINLOG | NULL | NUMERIC |
| ON | OPTIMIZE | OPTION |
| OPTIONALLY | OR | ORDER |
| OUT | OUTER | OUTFILE |
| PRECISION | PRIMARY | PROCEDURE |
| PURGE | RAID0 | RANGE |
| READ | READS | REAL |
| REFERENCES | REGEXP | RELEASE |
| RENAME | REPEAT | REPLACE |
| REQUIRE | RESTRICT | RETURN |
| REVOKE | RIGHT | RLIKE |
| SCHEMA | SCHEMAS | SECOND_MICROSECOND |
| SELECT | SENSITIVE | SEPARATOR |
| SET | SHOW | SMALLINT |
| SPATIAL | SPECIFIC | SQL |
| SQLEXCEPTION | SQLSTATE | SQLWARNING |
| SQL_BIG_RESULT | SQL_CALC_FOUND_ROWS | SQL_SMALL_RESULT |
| SSL | STARTING | STRAIGHT_JOIN |
| TABLE | TERMINATED | THEN |
| TINYBLOB | TINYINT | TINYTEXT |
| TO | TRAILING | TRIGGER |
| TRUE | UNDO | UNION |
| UNIQUE | UNLOCK | UNSIGNED |
| UPDATE | USAGE | USE |
| USING | UTC_DATE | UTC_TIME |
| UTC_TIMESTAMP | VALUES | VARBINARY |
| VARCHAR | VARCHARACTER | VARYING |
| WHEN | WHERE | WHILE |
| WITH | WRITE | X509 |
| XOR | YEAR_MONTH | ZEROFILL |
所以为了安全起见可以在表名和字段名上都加上``。