By default, strings can be enclosed by " as well as '. 默认情况下，字符串可以用"以及'括起来。If the ANSI_QUOTES SQL mode is enabled, strings can be enclosed only by ' and the server interprets strings enclosed by " as identifiers.如果启用了ANSI_QUOTES SQL模式，则字符串只能用'括起来，并且服务器将用"括起来的字符串解释为标识符。

\ is the escape character in strings.是字符串中的转义符。

In SQL statements, you can access tables from different databases with the db_name.tbl_name syntax. 在SQL语句中，可以使用db_name.tbl_name语法访问来自不同数据库的表。Some SQL servers provide the same functionality but call this User space. 某些SQL服务器提供相同的功能，但调用此User space。MySQL Server doesn't support tablespaces such as used in statements like this: CREATE TABLE ralph.my_table ... IN my_tablespace.MySQL Server不支持诸如以下语句中使用的表空间：CREATE TABLE ralph.my_table ... IN my_tablespace。

The ANALYZE TABLE, CHECK TABLE, OPTIMIZE TABLE, and REPAIR TABLE statements.ANALYZE TABLE、CHECK TABLE、OPTIMIZE TABLE和REPAIR TABLE 语句。

The CREATE DATABASE, DROP DATABASE, and ALTER DATABASE statements. See Section 13.1.12, “CREATE DATABASE Statement”, Section 13.1.24, “DROP DATABASE Statement”, and Section 13.1.2, “ALTER DATABASE Statement”.CREATE DATABASE、DROP DATABASE和ALTER DATABASE语句。请参阅第13.1.12节，“CREATE DATABASE语句”、第13.1.24节，“DROP DATABASE语句”和第13.1.2节，“ALTER DATABASE语句”。

The DO statement.DO语句。

EXPLAIN SELECT to obtain a description of how tables are processed by the query optimizer.EXPLAIN SELECT以获得查询优化器如何处理表的描述。

The FLUSH and RESET statements.FLUSH和RESET语句。

The SET statement. See Section 13.7.6.1, “SET Syntax for Variable Assignment”.SET语句。参见第13.7.6.1节，“变量赋值的SET语法”。

The SHOW statement. See Section 13.7.7, “SHOW Statements”. SHOW语句。参见第13.7.7节，“SHOW语句”。The information produced by many of the MySQL-specific SHOW statements can be obtained in more standard fashion by using SELECT to query INFORMATION_SCHEMA. 许多MySQL特有的SHOW语句产生的信息可以通过使用SELECT查询INFORMATION_SCHEMA以更标准的方式获得。See Chapter 26, INFORMATION_SCHEMA Tables.请参阅第26章，“INFORMATION_SCHEMA表格”。

Use of LOAD DATA. In many cases, this syntax is compatible with Oracle LOAD DATA. LOAD DATA的使用。在许多情况下，此语法与Oracle LOAD DATA兼容。See Section 13.2.7, “LOAD DATA Statement”.请参阅第13.2.7节，“LOAD DATA语句”。

Use of RENAME TABLE. See Section 13.1.36, “RENAME TABLE Statement”.RENAME TABLE的使用。参见第13.1.36节，“RENAME TABLE语句”。

Use of REPLACE instead of DELETE plus INSERT. 使用REPLACE而不是DELETE加INSERT。See Section 13.2.9, “REPLACE Statement”.请参阅第13.2.9节，“REPLACE语句”。

Use of CHANGE col_name, DROP col_name, or DROP INDEX, IGNORE or RENAME in ALTER TABLE statements. 在ALTER TABLE语句中使用CHANGE col_name、DROP col_name或DROP INDEX、IGNORE或RENAME。Use of multiple ADD, ALTER, DROP, or CHANGE clauses in an ALTER TABLE statement. 在ALTER TABLE语句中使用多个ADD、ALTER、DROP或CHANGE子句。See Section 13.1.9, “ALTER TABLE Statement”.请参阅第13.1.9节，“ALTER TABLE语句”。

Use of index names, indexes on a prefix of a column, and use of INDEX or KEY in CREATE TABLE statements. 在CREATE TABLE语句中使用索引名称、列前缀上的索引以及INDEX或KEY。See Section 13.1.20, “CREATE TABLE Statement”.请参阅第13.1.20节，“CREATE TABLE语句”。

Use of TEMPORARY or IF NOT EXISTS with CREATE TABLE.将TEMPORARY或IF NOT EXISTS与CREATE TABLE一起使用。

Use of IF EXISTS with DROP TABLE and DROP DATABASE.将IF EXISTS与DROP TABLE和DROP DATABASE一起使用。

The capability of dropping multiple tables with a single DROP TABLE statement.使用单个DROP TABLE语句删除多个表的功能。

The ORDER BY and LIMIT clauses of the UPDATE and DELETE statements.UPDATE和DELETE语句的ORDER BY和LIMIT子句。

INSERT INTO tbl_name SET col_name = ... syntax.INSERT INTO tbl_name SET col_name = ...语法。

The DELAYED clause of the INSERT and REPLACE statements.INSERT和REPLACE语句的DELAYED子句。

The LOW_PRIORITY clause of the INSERT, REPLACE, DELETE, and UPDATE statements.INSERT、REPLACE、DELETE和UPDATE语句的LOW_PRIORITY子句。

Use of INTO OUTFILE or INTO DUMPFILE in SELECT statements. 在SELECT语句中使用INTO OUTFILE或INTO DUMPFILE。See Section 13.2.10, “SELECT Statement”.请参阅第13.2.10节，“SELECT语句”。

Options such as STRAIGHT_JOIN or SQL_SMALL_RESULT in SELECT statements.SELECT语句中的STRIGHT_JOIN或SQL_SMALL_RESULT等选项。

You don't need to name all selected columns in the GROUP BY clause. 您不需要在GROUP BY子句中命名所有选定的列。This gives better performance for some very specific, but quite normal queries. 这为一些非常具体但非常正常的查询提供了更好的性能。See Section 12.20, “Aggregate Functions”.请参阅第12.20节，“聚合函数”。

You can specify ASC and DESC with GROUP BY, not just with ORDER BY.可以使用GROUP BY指定ASC和DESC，而不仅仅是使用ORDER BY。

The ability to set variables in a statement with the := assignment operator. 使用:=赋值运算符在语句中设置变量的能力。See Section 9.4, “User-Defined Variables”.请参阅第9.4节，“用户定义变量”。

The MEDIUMINT, SET, and ENUM data types, and the various BLOB and TEXT data types.MEDIUMINT、SET和ENUM数据类型，以及各种BLOB和TEXT数据类型

The AUTO_INCREMENT, BINARY, NULL, UNSIGNED, and ZEROFILL data type attributes.AUTO_INCREMENT、BINARY、NULL、UNSIGNED和ZEROFILL数据类型属性。

To make it easier for users who migrate from other SQL environments, MySQL Server supports aliases for many functions. For example, all string functions support both standard SQL syntax and ODBC syntax.为了方便从其他SQL环境迁移的用户，MySQL Server支持许多函数的别名。例如，所有字符串函数都支持标准SQL语法和ODBC语法。

MySQL Server understands the || and && operators to mean logical OR and AND, as in the C programming language. MySQL Server将||和&&运算符理解为逻辑OR和AND，就像在C编程语言中一样。In MySQL Server, || and OR are synonyms, as are && and AND. 在MySQL Server中，||和OR是同义词，&&和AND也是同义词。Because of this nice syntax, MySQL Server doesn't support the standard SQL || operator for string concatenation; use CONCAT() instead. 由于这种良好的语法，MySQL Server不支持标准的SQL ||运算符进行字符串连接；请改用CONCAT()。Because CONCAT() takes any number of arguments, it is easy to convert use of the || operator to MySQL Server.因为CONCAT()接受任意数量的参数，所以很容易将||运算符的使用转换为MySQL Server。

Use of COUNT(DISTINCT value_list) where value_list has more than one element.使用COUNT(DISTINCT value_list)，其中value_list有多个元素。

String comparisons are case-insensitive by default, with sort ordering determined by the collation of the current character set, which is utf8mb4 by default. 默认情况下，字符串比较不区分大小写，排序顺序由当前字符集的排序规则决定，默认情况下为utf8mb4。To perform case-sensitive comparisons instead, you should declare your columns with the BINARY attribute or use the BINARY cast, which causes comparisons to be done using the underlying character code values rather than a lexical ordering.要执行区分大小写的比较，您应该使用BINARY属性声明列，或者使用BINARY强制转换，这会导致使用基础字符代码值而不是词法排序来进行比较。

The % operator is a synonym for MOD(). %运算符是MOD()的同义词。That is, N % M is equivalent to MOD(N,M). 也就是说，N%M等于MOD(N,M)。% is supported for C programmers and for compatibility with PostgreSQL.%支持C程序员以及与PostgreSQL的兼容性。

The =, <>, <=, <, >=, >, <<, >>, <=>, AND, OR, or LIKE operators may be used in expressions in the output column list (to the left of the FROM) in SELECT statements. For example:=、<>、<=、<、>=、>、<<、>>、<=>、AND、OR或LIKE运算符可用于SELECT语句中输出列列表（FROM左侧）的表达式中。例如

mysql> SELECT col1=1 AND col2=2 FROM my_table;

The LAST_INSERT_ID() function returns the most recent AUTO_INCREMENT value. See Section 12.16, “Information Functions”.LAST_INSERT_ID()函数返回最新的AUTO_INCREMENT值。参见第12.16节，“信息函数”。

LIKE is permitted on numeric values.允许对数值使用LIKE。

The REGEXP and NOT REGEXP extended regular expression operators.REGEXP和NOT REGEXP扩展了正则表达式运算符。

CONCAT() or CHAR() with one argument or more than two arguments. (In MySQL Server, these functions can take a variable number of arguments.)具有一个参数或两个以上参数的CONCAT()或CHAR()。（在MySQL Server中，这些函数可以采用可变数量的参数。）

The BIT_COUNT(), CASE, ELT(), FROM_DAYS(), FORMAT(), IF(), MD5(), PERIOD_ADD(), PERIOD_DIFF(), TO_DAYS(), and WEEKDAY() functions.BIT_COUNT()、CASE、ELT()、FROM_DAYS()、FORMAT()、IF()、MD5()，PERIOD_ADD()、PERIOD_DIFF()、TO_DAYS()和WEEKDAY()函数。

Use of TRIM() to trim substrings. Standard SQL supports removal of single characters only.使用TRIM()修剪子字符串。标准SQL仅支持删除单个字符。

The GROUP BY functions STD(), BIT_OR(), BIT_AND(), BIT_XOR(), and GROUP_CONCAT(). GROUP BY函数STD()、BIT_OR()、BIT_AND()、BIT_XOR()和GROUP_CONNCT()。See Section 12.20, “Aggregate Functions”.请参阅第12.20节，“聚合函数”。