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TDSQL MySQL 版
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    最后更新时间：2024-01-06 12:31:07
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      语言结构

      分布式实例支持所有 MySQL 使用的文字格式，包括：
      String Literals
      Numeric Literals
      Date and Time Literals
      Hexadecimal Literals
      Bit-Value Literals
      Boolean Literals
      NULL Values

      String Literals

      String Literals 是一个 bytes 或者 characters 的序列，两端被单引号'或者双引号"包围，TDSQL MySQL版 目前不支持 ANSI_QUOTES SQL MODE，双引号"包围的始终认为是 String Literals，而不是 identifier。
      不支持 character set introducer，即[_charset_name]'string' [COLLATE collation_name]这种格式。
      支持的转义字符：
      \\0: ASCII NUL (X’00’) 字符
      \\‘: 单引号
      \\“: 双引号
      \\b: 退格符号
      \\n: 换行符
      \\r: 回车符
      \\t: tab 符（制表符）
      \\z: ASCII 26 (Ctrl + Z)
      \\\\: 反斜杠 \\
      \\%: \\%
      \\_: _

      Numeric Literals

      数值字面值包括 integer、Decimal 类型、浮点数字面值。 integer 可以包括.作为小数点分隔，数字前可以有-或者+来表示正数或者负数。 精确数值字面值可以表示为如下格式：1, .2, 3.4, -5, -6.78, +9.10。 科学记数法，如下格式：1.2E3, 1.2E-3, -1.2E3, -1.2E-3。

      Date and Time Literals

      DATE 支持如下格式：
      'YYYY-MM-DD' or 'YY-MM-DD'
      'YYYYMMDD' or 'YYMMDD'
      YYYYMMDD or YYMMDD
      
      如：'2012-12-31', '2012/12/31', '2012^12^31',  '2012@12@31'  '20070523' , '070523'
      DATETIME，TIMESTAMP 支持如下格式：
      'YYYY-MM-DD HH:MM:SS' or 'YY-MM-DD HH:MM:SS'
      'YYYYMMDDHHMMSS' or 'YYMMDDHHMMSS'
      YYYYMMDDHHMMSS or YYMMDDHHMMSS 
      
      如'2012-12-31 11:30:45', '2012^12^31 11+30+45', '2012/12/31 11*30*45',  '2012@12@31 11^30^45'，19830905132800

      Hexadecimal Literals

      支持格式如下：
      X'01AF'
      X'01af'
      x'01AF'
      x'01af'
      0x01AF
      0x01af

      Bit-Value Literals

      支持格式如下：
      b'01'
      B'01'
      0b01

      Boolean Literals

      常量 TRUE 和 FALSE 等于1和0，大小写不敏感。
      mysql>  SELECT TRUE, true, FALSE, false;
      +------+------+-------+-------+
      | TRUE | TRUE | FALSE | FALSE |
      +------+------+-------+-------+
      |    1 |    1 |     0 |     0 |
      +------+------+-------+-------+
      1 row in set (0.03 sec)

      NULL Values

      NULL 代表数据为空，大小写不敏感，与 \\N（大小写敏感）同义。 需要注意的是 NULL 跟0并不一样，跟空字符串''也不一样。

      字符集和时区

      支持 MySQL 的所有字符集和字符序：
      mysql> show character set;
      +----------+---------------------------------+---------------------+--------+
      | Charset  | Description                     | Default collation   | Maxlen |
      +----------+---------------------------------+---------------------+--------+
      | big5     | Big5 Traditional Chinese        | big5_chinese_ci     |      2 |
      | dec8     | DEC West European               | dec8_swedish_ci     |      1 |
      | cp850    | DOS West European               | cp850_general_ci    |      1 |
      | hp8      | HP West European                | hp8_english_ci      |      1 |
      | koi8r    | KOI8-R Relcom Russian           | koi8r_general_ci    |      1 |
      | latin1   | cp1252 West European            | latin1_swedish_ci   |      1 |
      | latin2   | ISO 8859-2 Central European     | latin2_general_ci   |      1 |
      | swe7     | 7bit Swedish                    | swe7_swedish_ci     |      1 |
      | ascii    | US ASCII                        | ascii_general_ci    |      1 |
      | ujis     | EUC-JP Japanese                 | ujis_japanese_ci    |      3 |
      | sjis     | Shift-JIS Japanese              | sjis_japanese_ci    |      2 |
      | hebrew   | ISO 8859-8 Hebrew               | hebrew_general_ci   |      1 |
      | tis620   | TIS620 Thai                     | tis620_thai_ci      |      1 |
      | euckr    | EUC-KR Korean                   | euckr_korean_ci     |      2 |
      | koi8u    | KOI8-U Ukrainian                | koi8u_general_ci    |      1 |
      | gb2312   | GB2312 Simplified Chinese       | gb2312_chinese_ci   |      2 |
      | greek    | ISO 8859-7 Greek                | greek_general_ci    |      1 |
      | cp1250   | Windows Central European        | cp1250_general_ci   |      1 |
      | gbk      | GBK Simplified Chinese          | gbk_chinese_ci      |      2 |
      | latin5   | ISO 8859-9 Turkish              | latin5_turkish_ci   |      1 |
      | armscii8 | ARMSCII-8 Armenian              | armscii8_general_ci |      1 |
      | utf8     | UTF-8 Unicode                   | utf8_general_ci     |      3 |
      | ucs2     | UCS-2 Unicode                   | ucs2_general_ci     |      2 |
      | cp866    | DOS Russian                     | cp866_general_ci    |      1 |
      | keybcs2  | DOS Kamenicky Czech-Slovak      | keybcs2_general_ci  |      1 |
      | macce    | Mac Central European            | macce_general_ci    |      1 |
      | macroman | Mac West European               | macroman_general_ci |      1 |
      | cp852    | DOS Central European            | cp852_general_ci    |      1 |
      | latin7   | ISO 8859-13 Baltic              | latin7_general_ci   |      1 |
      | utf8mb4  | UTF-8 Unicode                   | utf8mb4_general_ci  |      4 |
      | cp1251   | Windows Cyrillic                | cp1251_general_ci   |      1 |
      | utf16    | UTF-16 Unicode                  | utf16_general_ci    |      4 |
      | utf16le  | UTF-16LE Unicode                | utf16le_general_ci  |      4 |
      | cp1256   | Windows Arabic                  | cp1256_general_ci   |      1 |
      | cp1257   | Windows Baltic                  | cp1257_general_ci   |      1 |
      | utf32    | UTF-32 Unicode                  | utf32_general_ci    |      4 |
      | binary   | Binary pseudo charset           | binary              |      1 |
      | geostd8  | GEOSTD8 Georgian                | geostd8_general_ci  |      1 |
      | cp932    | SJIS for Windows Japanese       | cp932_japanese_ci   |      2 |
      | eucjpms  | UJIS for Windows Japanese       | eucjpms_japanese_ci |      3 |
      | gb18030  | China National Standard GB18030 | gb18030_chinese_ci  |      4 |
      +----------+---------------------------------+---------------------+--------+
      41 rows in set (0.02 sec)
      查看当前连接的字符集：
      mysql> show variables like "%char%";
      +--------------------------+-----------------------------------------------------+
      | Variable_name            | Value                                               |
      +--------------------------+-----------------------------------------------------+
      | character_set_client     | latin1                                              |
      | character_set_connection | latin1                                              |
      | character_set_database   | utf8                                                |
      | character_set_filesystem | binary                                              |
      | character_set_results    | latin1                                              |
      | character_set_server     | utf8                                                |
      | character_set_system     | utf8                                                |
      | character_sets_dir       | /data/tdsql_run/8812/percona-5.7.17/share/charsets/ |
      +--------------------------+-----------------------------------------------------+
      设置当前连接相关的字符集：
      mysql> set names utf8;
      Query OK, 0 rows affected (0.03 sec)
      
      mysql> show variables like "%char%";
      +--------------------------+-----------------------------------------------------+
      | Variable_name            | Value                                               |
      +--------------------------+-----------------------------------------------------+
      | character_set_client     | utf8                                                |
      | character_set_connection | utf8                                                |
      | character_set_database   | utf8                                                |
      | character_set_filesystem | binary                                              |
      | character_set_results    | utf8                                                |
      | character_set_server     | utf8                                                |
      | character_set_system     | utf8                                                |
      | character_sets_dir       | /data/tdsql_run/8811/percona-5.7.17/share/charsets/ |
      +--------------------------+-----------------------------------------------------+
      说明：
      分布式实例不支持设置全局参数，需要调用前台接口设置。
      支持通过设置 time_zone 变量修改时区相关的属性：
      mysql> show variables like '%time_zone%';
      +------------------+--------+
      | Variable_name    | Value  |
      +------------------+--------+
      | system_time_zone | CST    |
      | time_zone        | SYSTEM |
      +------------------+--------+
      2 rows in set (0.00 sec)
      
      mysql> create table test.tt (ts timestamp, dt datetime,c int) shardkey=c;
      Query OK, 0 rows affected (0.49 sec)
      
      mysql>  insert into test.tt (ts,dt,c)values ('2017-10-01 12:12:12', '2017-10-01 12:12:12',1);
      Query OK, 1 row affected (0.09 sec)
      
      mysql> select * from test.tt;
      +---------------------+---------------------+------+
      | ts                  | dt                  | c    |
      +---------------------+---------------------+------+
      | 2017-10-01 12:12:12 | 2017-10-01 12:12:12 |    1 |
      +---------------------+---------------------+------+
      1 row in set (0.04 sec)
      
      mysql> set time_zone = '+12:00';
      Query OK, 0 rows affected (0.00 sec)
      
      mysql> show variables like '%time_zone%';
      +------------------+--------+
      | Variable_name    | Value  |
      +------------------+--------+
      | system_time_zone | CST    |
      | time_zone        | +12:00 |
      +------------------+--------+
      2 rows in set (0.00 sec)
      
      mysql> select * from test.tt;
      +---------------------+---------------------+------+
      | ts                  | dt                  | c    |
      +---------------------+---------------------+------+
      | 2017-10-01 16:12:12 | 2017-10-01 12:12:12 |    1 |
      +---------------------+---------------------+------+
      1 row in set (0.06 sec)

      数据类型

      支持 MySQL 的所有数据类型，包括数字，字符，日期，空间类型，JSON。

      数字

      整型支持 INTEGER， INT，SMALLINT，TINYINT，MEDIUMINT，BIGINT。
      类型
      字节数
      最小值（有符号/无符号）
      最大值（有符号/无符号）
      TINYINT
      1
      -128/0
      127/255
      SMALLINT
      2
      -32768/0
      32767/65535
      MEDIUMINT
      3
      -8388608/0
      8388607/16777215
      INT
      4
      -2147483648/0
      2147483647/4294967295
      BIGINT
      8
      -9223372036854775808/0
      9223372036854775807/18446744073709551615
      浮点类型支持 FLOAT 和 DOUBLE，格式 FLOAT(M,D) 、REAL(M,D) 或 DOUBLE PRECISION(M,D)
      定点类型支持 DECIMAL和NUMERIC，格式 DECIMAL(M,D)

      字符

      支持如下字符类型：
      CHAR 和 VARCHAR Types
      BINARY 和 VARBINARY Types
      BLOB 和 TEXT Types
          TINYBLOB，TINYTEXT，MEDIUMBLOB,MEDIUMTEXT，LONGBLOB，LONGTEXT
      ENUM Type
      SET Type

      日期

      支持如下时间类型：
      DATE, DATETIME,  TIMESTAMP Types
      TIME Type
      YEAR Type

      空间

      支持如下空间类型：
      GEOMETRY
      POINT
      LINESTRING
      POLYGON
      
      MULTIPOINT
      MULTILINESTRING
      MULTIPOLYGON
      GEOMETRYCOLLECTION

      JSON

      支持存储 JSON 格式的数据，使得对 JSON 处理更加有效，同时又能提早检查错误：
      注意：
      对 JSON 类型的字段进行排序时，不支持混合类型排序。如不能将 string 类型和 int 类型做比较，同类型排序只支持数值类型，string 类型，其它类型排序不处理。对下表来说，不支持select * from t1 order by t1->"$.key2"，因为排序列中包含了数值和字符串类型。
      mysql>  CREATE TABLE t1 (jdoc JSON,a int) shardkey=a;
      Query OK, 0 rows affected (0.30 sec)
      
      mysql> INSERT INTO t1 (jdoc,a)VALUES('{"key1": "value1", "key2": "value2"}',1);
      Query OK, 1 row affected (0.00 sec)
      
      mysql> INSERT INTO t1 (jdoc,a)VALUES('{"key1": "value1", "key2": 2}',2);
      
      mysql> INSERT INTO t1 (jdoc,a)VALUES('[1, 2,',5);
      ERROR 3140 (22032): Invalid JSON text: "Invalid value." at position 6 in value for column 't1.jdoc'.
      
      mysql> select * from t1;
      +--------------------------------------+---+
      | jdoc                                 | a |
      +--------------------------------------+---+
      | {"key1": "value1", "key2": "value2"} | 1 |
      | {"key1": "value1", "key2": 2}        | 2 |
      +--------------------------------------+---+
      2 rows in set (0.00 sec)
      

      函数支持

      Control Flow Functions
      Name
      Description
      CASE
      Case operator
      IF()
      If/else construct
      IFNULL()
      Null if/else construct
      NULLIF()
      Return NULL if expr1 = expr2
      String Functions
      Name
      Description
      ASCII()
      Return numeric value of left-most character
      BIN()
      Return a string containing binary representation of a number
      BIT_LENGTH()
      Return length of argument in bits
      CHAR()
      Return the character for each integer passed
      CHAR_LENGTH()
      Return number of characters in argument
      CHARACTER_LENGTH()
      Synonym for CHAR_LENGTH()
      CONCAT()
      Return concatenated string
      CONCAT_WS()
      Return concatenate with separator
      ELT()
      Return string at index number
      EXPORT_SET()
      Return a string such that for every bit set in the value bits, you get an on string and for every unset bit, you get an off string
      FIELD()
      Return the index (position) of the first argument in the subsequent arguments
      FIND_IN_SET()
      Return the index position of the first argument within the second argument
      FORMAT()
      Return a number formatted to specified number of decimal places
      FROM_BASE64()
      Decode to a base-64 string and return result
      HEX()
      Return a hexadecimal representation of a decimal or string value
      INSERT()
      Insert a substring at the specified position up to the specified number of characters
      INSTR()
      Return the index of the first occurrence of substring
      LCASE()
      Synonym for LOWER()
      LEFT()
      Return the leftmost number of characters as specified
      LENGTH()
      Return the length of a string in bytes
      LIKE
      Simple pattern matching
      LOAD_FILE()
      Load the named file
      LOCATE()
      Return the position of the first occurrence of substring
      LOWER()
      Return the argument in lowercase
      LPAD()
      Return the string argument, left-padded with the specified string
      LTRIM()
      Remove leading spaces
      MAKE_SET()
      Return a set of comma-separated strings that have the corresponding bit in bits set
      MATCH
      Perform full-text search
      MID()
      Return a substring starting from the specified position
      NOT LIKE
      Negation of simple pattern matching
      NOT REGEXP
      Negation of REGEXP
      OCT()
      Return a string containing octal representation of a number
      OCTET_LENGTH()
      Synonym for LENGTH()
      ORD()
      Return character code for leftmost character of the argument
      POSITION()
      Synonym for LOCATE()
      QUOTE()
      Escape the argument for use in an SQL statement
      REGEXP
      Pattern matching using regular expressions
      REPEAT()
      Repeat a string the specified number of times
      REPLACE()
      Replace occurrences of a specified string
      REVERSE()
      Reverse the characters in a string
      RIGHT()
      Return the specified rightmost number of characters
      RLIKE
      Synonym for REGEXP
      RPAD()
      Append string the specified number of times
      RTRIM()
      Remove trailing spaces
      SOUNDEX()
      Return a soundex string
      SOUNDS LIKE
      Compare sounds
      SPACE()
      Return a string of the specified number of spaces
      STRCMP()
      Compare two strings
      SUBSTR()
      Return the substring as specified
      SUBSTRING()
      Return the substring as specified
      SUBSTRING_INDEX()
      Return a substring from a string before the specified number of occurrences of the delimiter
      TO_BASE64()
      Return the argument converted to a base-64 string
      TRIM()
      Remove leading and trailing spaces
      UCASE()
      Synonym for UPPER()
      UNHEX()
      Return a string containing hex representation of a number
      UPPER()
      Convert to uppercase
      WEIGHT_STRING()
      Return the weight string for a string
      Numeric Functions and Operators
      Name
      Description
      ABS()
      Return the absolute value
      ACOS()
      Return the arc cosine
      ASIN()
      Return the arc sine
      ATAN()
      Return the arc tangent
      ATAN2(), ATAN()
      Return the arc tangent of the two arguments
      CEIL()
      Return the smallest integer value not less than the argument
      CEILING()
      Return the smallest integer value not less than the argument
      CONV()
      Convert numbers between different number bases
      COS()
      Return the cosine
      COT()
      Return the cotangent
      CRC32()
      Compute a cyclic redundancy check value
      DEGREES()
      Convert radians to degrees
      DIV
      Integer division
      /
      Division operator
      EXP()
      Raise to the power of
      FLOOR()
      Return the largest integer value not greater than the argument
      LN()
      Return the natural logarithm of the argument
      LOG()
      Return the natural logarithm of the first argument
      LOG10()
      Return the base-10 logarithm of the argument
      LOG2()
      Return the base-2 logarithm of the argument
      -
      Minus operator
      MOD()
      Return the remainder
      %, MOD
      Modulo operator
      PI()
      Return the value of pi
      +
      Addition operator
      POW()
      Return the argument raised to the specified power
      POWER()
      Return the argument raised to the specified power
      RADIANS()
      Return argument converted to radians
      RAND()
      Return a random floating-point value
      ROUND()
      Round the argument
      SIGN()
      Return the sign of the argument
      SIN()
      Return the sine of the argument
      SQRT()
      Return the square root of the argument
      TAN()
      Return the tangent of the argument
      *
      Multiplication operator
      TRUNCATE()
      Truncate to specified number of decimal places
      -
      Change the sign of the argument
      Date and Time Functions
      Name
      Description
      ADDDATE()
      Add time values (intervals) to a date value
      ADDTIME()
      Add time
      CONVERT_TZ()
      Convert from one time zone to another
      CURDATE()
      Return the current date
      CURRENT_DATE(), CURRENT_DATE
      Synonyms for CURDATE()
      CURRENT_TIME(), CURRENT_TIME
      Synonyms for CURTIME()
      CURRENT_TIMESTAMP(), CURRENT_TIMESTAMP
      Synonyms for NOW()
      CURTIME()
      Return the current time
      DATE()
      Extract the date part of a date or datetime expression
      DATE_ADD()
      Add time values (intervals) to a date value
      DATE_FORMAT()
      Format date as specified
      DATE_SUB()
      Subtract a time value (interval) from a date
      DATEDIFF()
      Subtract two dates
      DAY()
      Synonym for DAYOFMONTH()
      DAYNAME()
      Return the name of the weekday
      DAYOFMONTH()
      Return the day of the month (0-31)
      DAYOFWEEK()
      Return the weekday index of the argument
      DAYOFYEAR()
      Return the day of the year (1-366)
      EXTRACT()
      Extract part of a date
      FROM_DAYS()
      Convert a day number to a date
      FROM_UNIXTIME()
      Format Unix timestamp as a date
      GET_FORMAT()
      Return a date format string
      HOUR()
      Extract the hour
      LAST_DAY
      Return the last day of the month for the argument
      LOCALTIME(), LOCALTIME
      Synonym for NOW()
      LOCALTIMESTAMP, LOCALTIMESTAMP()
      Synonym for NOW()
      MAKEDATE()
      Create a date from the year and day of year
      MAKETIME()
      Create time from hour, minute, second
      MICROSECOND()
      Return the microseconds from argument
      MINUTE()
      Return the minute from the argument
      MONTH()
      Return the month from the date passed
      MONTHNAME()
      Return the name of the month
      NOW()
      Return the current date and time
      PERIOD_ADD()
      Add a period to a year-month
      PERIOD_DIFF()
      Return the number of months between periods
      QUARTER()
      Return the quarter from a date argument
      SEC_TO_TIME()
      Converts seconds to 'HH:MM:SS' format
      SECOND()
      Return the second (0-59)
      STR_TO_DATE()
      Convert a string to a date
      SUBDATE()
      Synonym for DATE_SUB() when invoked with three arguments
      SUBTIME()
      Subtract times
      SYSDATE()
      Return the time at which the function executes
      TIME()
      Extract the time portion of the expression passed
      TIME_FORMAT()
      Format as time
      TIME_TO_SEC()
      Return the argument converted to seconds
      TIMEDIFF()
      Subtract time
      TIMESTAMP()
      With a single argument, this function returns the date or datetime expression; with two arguments, the sum of the arguments
      TIMESTAMPADD()
      Add an interval to a datetime expression
      TIMESTAMPDIFF()
      Subtract an interval from a datetime expression
      TO_DAYS()
      Return the date argument converted to days
      TO_SECONDS()
      Return the date or datetime argument converted to seconds since Year 0
      UNIX_TIMESTAMP()
      Return a Unix timestamp
      UTC_DATE()
      Return the current UTC date
      UTC_TIME()
      Return the current UTC time
      UTC_TIMESTAMP()
      Return the current UTC date and time
      WEEK()
      Return the week number
      WEEKDAY()
      Return the weekday index
      WEEKOFYEAR()
      Return the calendar week of the date (1-53)
      YEAR()
      Return the year
      YEARWEEK()
      Return the year and week
      Aggregate (GROUP BY) Functions
      Name
      Description
      AVG()
      Return the average value of the argument
      COUNT()
      Return a count of the number of rows returned
      MAX()
      Return the maximum value
      MIN()
      Return the minimum value
      SUM()
      Return the sum
      Bit Functions and Operators
      Name
      Description
      BIT_COUNT()
      Return the number of bits that are set
      &
      Bitwise AND
      ~
      Bitwise inversion
      \\
      Bitwise OR
      ^
      Bitwise XOR
      <<
      Left shift
      >>
      Right shift
      Cast Functions and Operators
      Name
      Description
      BINARY
      Cast a string to a binary string
      CAST()
      Cast a value as a certain type
      CONVERT()
      Cast a value as a certain type
      
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