PolarDB-X 1.0 is compatible with most MySQL 5.7 functions. This page lists the supported function categories and the specific functions that are not supported.
Supported function categories
PolarDB-X 1.0 supports the following function categories:
Date and time functions
String functions
Conversion functions
Aggregate functions
Mathematical functions
Comparison functions
Bit functions
Flow control functions
Information functions
Encryption functions
Compression functions
Other functions
JSON functions and geographic information functions are supported through pushdown execution only.
Unsupported MySQL 5.7 function categories
The following MySQL 5.7 function categories are not supported in PolarDB-X 1.0:
Functions unsupported in WHERE clauses and UPDATE statements
The following functions are not supported in WHERE clauses or UPDATE statements:
LAST_INSERT_ID()CONNECTION_ID()CURRENT_USER()CURRENT_USER DATABASE()SCHEMA()USER()VERSION()
Unsupported functions by category
The following functions belong to supported categories but are not available in PolarDB-X 1.0. Functions marked as deprecated were already deprecated in MySQL 5.7 and are not supported because they do not align with current best practices.
Date and time functions
| Function | Description |
|---|---|
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() |
String functions
| Function | Description |
|---|---|
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 |
Aggregate functions
| Function | Description |
|---|---|
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 |
Mathematical functions
| Function | Description |
|---|---|
RADIANS() | Return argument converted to radians |
Information functions
| Function | Description |
|---|---|
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, return the number of rows that would be returned without the LIMIT clause |
ROW_COUNT() | Return the number of rows updated |
Encryption and compression functions
Functions marked as deprecated were already deprecated in MySQL 5.7 and are not supported. All other functions in this section are not available in PolarDB-X 1.0.
| Function | Description | Status |
|---|---|---|
ASYMMETRIC_DECRYPT() | Decrypt ciphertext using a private or public key | Not supported |
ASYMMETRIC_DERIVE() | Derive a symmetric key from asymmetric keys | Not supported |
ASYMMETRIC_ENCRYPT() | Encrypt cleartext using a private or public key | Not supported |
ASYMMETRIC_SIGN() | Generate a signature from a digest | Not supported |
ASYMMETRIC_VERIFY() | Verify that a signature matches a digest | Not supported |
CREATE_ASYMMETRIC_PRIV_KEY() | Create a private key | Not supported |
CREATE_ASYMMETRIC_PUB_KEY() | Create a public key | Not supported |
CREATE_DH_PARAMETERS() | Generate a shared DH secret | Not supported |
CREATE_DIGEST() | Generate a digest from a string | Not supported |
RANDOM_BYTES() | Return a random byte vector | Not supported |
SHA1(), SHA() | Calculate an SHA-1 160-bit checksum | Not supported |
SHA2() | Calculate an SHA-2 checksum | Not supported |
VALIDATE_PASSWORD_STRENGTH() | Determine password strength | Not supported |
DECODE() | Decode a string encrypted using ENCODE() | Deprecated in MySQL 5.7.2 |
DES_DECRYPT() | Decrypt a string | Deprecated in MySQL 5.7.6 |
DES_ENCRYPT() | Encrypt a string | Deprecated in MySQL 5.7.6 |
ENCODE() | Encode a string | Deprecated in MySQL 5.7.2 |
ENCRYPT() | Encrypt a string | Deprecated in MySQL 5.7.6 |
OLD_PASSWORD() | Return the pre-4.1 implementation of PASSWORD | Not supported |
PASSWORD() | Calculate and return a password string | Deprecated in MySQL 5.7.6 |
Other functions
| Function | Description |
|---|---|
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 the argument is an IPv4 address |
IS_IPV4_COMPAT() | Whether the argument is an IPv4-compatible address |
IS_IPV4_MAPPED() | Whether the argument is an IPv4-mapped address |
IS_IPV6() | Whether the argument is an IPv6 address |
IS_USED_LOCK() | Whether the named lock is in use; return the connection identifier if true |
MASTER_POS_WAIT() | Block until the replica has read and applied all updates up to the specified position |
NAME_CONST() | Cause the column to have the given name |