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函数

更新时间:2018-12-01 12:41:02

DRDS 支持的函数分为日期时间函数、字符串函数、转换函数、聚合函数、数学函数、比较函数、位函数、控制流程函数、信息函数、加密和压缩函数以及其他函数;JSON 函数和地理信息函数的下推执行。

以下函数出现在WHERE条件、UPDATE语句中,DRDS不支持:LAST_INSERT_ID()CONNECTION_ID()CURRENT_USER(), CURRENT_USERDATABASE()SCHEMA()USER()VERSION()

与 MySQL5.7 相比,DRDS 不支持以下几类函数:

已经支持的几类函数中,有如下函数不支持:

类别
函数名
描述
日期时间函数
CONVERT_TZ()
Convert from one time zone to another
GET_FORMAT()
Return a date format string
LOCALTIME(), LOCALTIME
Synonym for NOW()
LOCALTIMESTAMP, LOCALTIMESTAMP()
Synonym for NOW()
字符串函数
FIND_IN_SET()
Return the index position of the first argument within the second argument
LOAD_FILE()
Load the named file
MATCH
Perform full-text search
SOUNDS LIKE
Compare sounds
聚合函数
BIT_AND(
Return bitwise AND
BIT_OR()
Return bitwise OR
BIT_XOR()
Return bitwise XOR
GROUP_CONCAT()
Return a concatenated string
STD()
Return the population standard deviation
STDDEV()
Return the population standard deviation
STDDEV_POP()
Return the population standard deviation
STDDEV_SAMP()
Return the sample standard deviation
VAR_POP()
Return the population standard variance
VAR_SAMP()
Return the sample variance
VARIANCE()
Return the population standard variance
数学函数
RADIANS()
Return argument converted to radians
信息函数
BENCHMARK()
Repeatedly execute an expression
CHARSET()
Return the character set of the argument
COERCIBILITY()
Return the collation coercibility value of the string argument
COLLATION()
Return the collation of the string argument
FOUND_ROWS()
For a SELECT with a LIMIT clause, the number of rows that would be returned were there no LIMIT clause
ROW_COUNT()
The number of rows updated
加密和压缩函数
ASYMMETRIC_DECRYPT()
Decrypt ciphertext using private or public key
ASYMMETRIC_DERIVE()
Derive symmetric key from asymmetric keys
ASYMMETRIC_ENCRYPT()
Encrypt cleartext using private or public key
ASYMMETRIC_SIGN()
Generate signature from digest
ASYMMETRIC_VERIFY()
Verify that signature matches digest
CREATE_ASYMMETRIC_PRIV_KEY()
Create private key
CREATE_ASYMMETRIC_PUB_KEY()
Create public key
CREATE_DH_PARAMETERS()
Generate shared DH secret
CREATE_DIGEST()
Generate digest from string
DECODE() (deprecated 5.7.2)
Decodes a string encrypted using ENCODE()
DES_DECRYPT() (deprecated 5.7.6)
Decrypt a string
DES_ENCRYPT() (deprecated 5.7.6)
Encrypt a string
ENCODE() (deprecated 5.7.2)
Encode a string
ENCRYPT() (deprecated 5.7.6)
Encrypt a string
OLD_PASSWORD()
Return the value of the pre-4.1 implementation of PASSWORD
PASSWORD() (deprecated 5.7.6)
Calculate and return a password string
RANDOM_BYTES()
Return a random byte vector
SHA1(), SHA()
Calculate an SHA-1 160-bit checksum
SHA2()
Calculate an SHA-2 checksum
VALIDATE_PASSWORD_STRENGTH()
Determine strength of password
其他函数
ANY_VALUE()
Suppress ONLY_FULL_GROUP_BY value rejection
DEFAULT()
Return the default value for a table column
GET_LOCK()
Get a named lock
INET_ATON()
Return the numeric value of an IP address
INET_NTOA()
Return the IP address from a numeric value
INET6_ATON()
Return the numeric value of an IPv6 address
INET6_NTOA()
Return the IPv6 address from a numeric value
IS_FREE_LOCK()
Whether the named lock is free
IS_IPV4()
Whether argument is an IPv4 address
IS_IPV4_COMPAT()
Whether argument is an IPv4-compatible address
IS_IPV4_MAPPED()
Whether argument is an IPv4-mapped address
IS_IPV6()
Whether argument is an IPv6 address
IS_USED_LOCK()
Whether the named lock is in use; return connection identifier if true
MASTER_POS_WAIT()
Block until the slave has read and applied all updates up to the specified position
NAME_CONST()
Causes the column to have the given name