- 如果能保证SQL会将函数整体下发给某个后端结点，函数支持度没有意义，支持度将托管于MySQL.
- 在2.18.09.0 版本之前（含），涉及到中文字符集的字符串相关函数有bug。
- 除了聚合函数经过充分测试之外，其余函数只进行了简单的测试，并没有全覆盖测试，请使用前充分测试 。
- 未在列表中的函数，一概不支持。
| Name | Description | Support |
|---|---|---|
| AND, && | Logical AND | Y |
| = | Assign a value (as part of a SET statement, or as part of the SET clause in an UPDATE statement) | Y |
| := | Assign a value | N |
| BETWEEN ... AND ... | Check whether a value is within a range of values | Y |
| BINARY | Cast a string to a binary string | N |
| & | Bitwise AND | Y |
| ~ | Bitwise inversion | Y |
| | | Bitwise OR | Y |
| ^ | Bitwise XOR | Y |
| CASE | Case operator | Y |
| DIV | Integer division | Y |
| / | Division operator | Y |
| = | Equal operator | Y |
| <=> | NULL-safe equal to operator | Y |
| > | Greater than operator | Y |
| >= | Greater than or equal operator | Y |
| IS | Test a value against a boolean | Y |
| IS NOT | Test a value against a boolean | Y |
| IS NOT NULL | NOT NULL value test | Y |
| IS NULL | NULL value test | Y |
| -> | Return value from JSON column after evaluating path; equivalent to JSON_EXTRACT(). | N |
| ->> | Return value from JSON column after evaluating path and unquoting the result; equivalent to JSON_UNQUOTE(JSON_EXTRACT()). | N |
| << | Left shift | Y |
| < | Less than operator | Y |
| <= | Less than or equal operator | Y |
| LIKE | Simple pattern matching | Y |
| - | Minus operator | Y |
| %, MOD | Modulo operator | Y |
| NOT, ! | Negates value | Y |
| NOT BETWEEN ... AND ... | Check whether a value is not within a range of values | Y |
| !=, <> | Not equal operator | Y |
| NOT LIKE | Negation of simple pattern matching | Y |
| NOT REGEXP | Negation of REGEXP | Y |
| ||, OR | Logical OR | Y |
| + | Addition operator | Y |
| REGEXP | Whether string matches regular expression | Y |
| >> | Right shift | Y |
| RLIKE | Whether string matches regular expression | N |
| SOUNDS LIKE | Compare sounds | N |
| * | Multiplication operator | N |
| - | Change the sign of the argument | Y |
| XOR | Logical XOR | Y |
| COALESCE() | Return the first non-NULL argument | Y |
| GREATEST() | Return the largest argument | Y |
| IN() | Check whether a value is within a set of values | Y |
| INTERVAL() | Return the index of the argument that is less than the first argument | Y |
| ISNULL() | Test whether the argument is NULL | Y |
| LEAST() | Return the smallest argument | Y |
| STRCMP() | Compare two strings | Y |
| Name | Description | Support |
|---|---|---|
| CASE | Case operator | Y |
| IF() | If/else construct | Y |
| IFNULL() | Null if/else construct | Y |
| NULLIF() | Return NULL if expr1 = expr2 | Y |
| Name | Description | Support |
|---|---|---|
| ASCII() | Return numeric value of left-most character | Y |
| BIN() | Return a string containing binary representation of a number | N |
| BIT_LENGTH() | Return length of argument in bits | Y |
| CHAR() | Return the character for each integer passed | Y |
| CHAR_LENGTH() | Return number of characters in argument | Y |
| CHARACTER_LENGTH() | Synonym for CHAR_LENGTH() | Y |
| CONCAT() | Return concatenated string | Y |
| CONCAT_WS() | Return concatenate with separator | Y |
| ELT() | Return string at index number | Y |
| 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 | N |
| FIELD() | Return the index (position) of the first argument in the subsequent arguments | Y |
| FIND_IN_SET() | Return the index position of the first argument within the second argument | Y |
| FORMAT() | Return a number formatted to specified number of decimal places | Y |
| FROM_BASE64() | Decode base64 encoded string and return result | N |
| HEX() | Return a hexadecimal representation of a decimal or string value | Y |
| INSERT() | Insert a substring at the specified position up to the specified number of characters | Y |
| INSTR() | Return the index of the first occurrence of substring | Y |
| LCASE() | Synonym for LOWER() | Y |
| LEFT() | Return the leftmost number of characters as specified | Y |
| LENGTH() | Return the length of a string in bytes | Y |
| LIKE | Simple pattern matching | Y |
| LOAD_FILE() | Load the named file | N |
| LOCATE() | Return the position of the first occurrence of substring | Y |
| LOWER() | Return the argument in lowercase | Y |
| LPAD() | Return the string argument, left-padded with the specified string | Y |
| LTRIM() | Remove leading spaces | Y |
| MAKE_SET() | Return a set of comma-separated strings that have the corresponding bit in bits set | Y |
| MATCH | Perform full-text search | N |
| MID() | Return a substring starting from the specified position | N |
| NOT LIKE | Negation of simple pattern matching | Y |
| NOT REGEXP | Negation of REGEXP | Y |
| OCT() | Return a string containing octal representation of a number | N |
| OCTET_LENGTH() | Synonym for LENGTH() | N |
| ORD() | Return character code for leftmost character of the argument | Y |
| POSITION() | Synonym for LOCATE() | N |
| QUOTE() | Escape the argument for use in an SQL statement | Y |
| REGEXP | Whether string matches regular expression | Y |
| REPEAT() | Repeat a string the specified number of times | Y |
| REPLACE() | Replace occurrences of a specified string | Y |
| REVERSE() | Reverse the characters in a string | Y |
| RIGHT() | Return the specified rightmost number of characters | Y |
| RLIKE | Whether string matches regular expression | N |
| RPAD() | Append string the specified number of times | Y |
| RTRIM() | Remove trailing spaces | Y |
| SOUNDEX() | Return a soundex string | Y |
| SOUNDS LIKE | Compare sounds | Y |
| SPACE() | Return a string of the specified number of spaces | Y |
| STRCMP() | Compare two strings | Y |
| SUBSTR() | Return the substring as specified | Y |
| SUBSTRING() | Return the substring as specified | Y |
| SUBSTRING_INDEX() | Return a substring from a string before the specified number of occurrences of the delimiter | Y |
| TO_BASE64() | Return the argument converted to a base-64 string | N |
| TRIM() | Remove leading and trailing spaces | Y |
| UCASE() | Synonym for UPPER() | Y |
| UNHEX() | Return a string containing hex representation of a number | Y |
| UPPER() | Convert to uppercase | Y |
| WEIGHT_STRING() | Return the weight string for a string | N |
由于 MySQL 文档中，只说明了 HEX 作用于小整数（<=64位）和string 的情况。没有具体说明大整数（>64位）和浮点数这类比较极端的情况。在以上这些极端情况下，MySQL 8.0 和 MySQL 5.7 的结果不一定一致。 dble 的 HEX 结果和 MySQL 8 实现保持一致，但建议用户不要过度依赖这个结果。
| Name | Description | Support |
|---|---|---|
| ABS() | Return the absolute value | Y |
| ACOS() | Return the arc cosine | Y |
| ASIN() | Return the arc sine | Y |
| ATAN() | Return the arc tangent | Y |
| ATAN2(), ATAN() | Return the arc tangent of the two arguments | Y |
| CEIL() | Return the smallest integer value not less than the argument | Y |
| CEILING() | Return the smallest integer value not less than the argument | Y |
| CONV() | Convert numbers between different number bases | Y |
| COS() | Return the cosine | Y |
| COT() | Return the cotangent | Y |
| CRC32() | Compute a cyclic redundancy check value | Y |
| DEGREES() | Convert radians to degrees | Y |
| DIV | Integer division | Y |
| / | Division operator | Y |
| EXP() | Raise to the power of | Y |
| FLOOR() | Return the largest integer value not greater than the argument | Y |
| LN() | Return the natural logarithm of the argument | Y |
| LOG() | Return the natural logarithm of the first argument | Y |
| LOG10() | Return the base-10 logarithm of the argument | Y |
| LOG2() | Return the base-2 logarithm of the argument | Y |
| - | Minus operator | Y |
| MOD() | Return the remainder | N (If the SQL pass through, still supported) |
| %, MOD | Modulo operator | Y |
| PI() | Return the value of pi | Y |
| + | Addition operator | Y |
| POW() | Return the argument raised to the specified power | Y |
| POWER() | Return the argument raised to the specified power | Y |
| RADIANS() | Return argument converted to radians | Y |
| RAND() | Return a random floating-point value | Y |
| ROUND() | Round the argument | Y |
| SIGN() | Return the sign of the argument | Y |
| SIN() | Return the sine of the argument | Y |
| SQRT() | Return the square root of the argument | Y |
| TAN() | Return the tangent of the argument | Y |
| * | Multiplication operator | Y |
| TRUNCATE() | Truncate to specified number of decimal places | Y |
| - | Change the sign of the argument | Y |
| Name | Description | Support |
|---|---|---|
| ADDDATE() | Add time values (intervals) to a date value | Y |
| ADDTIME() | Add time | Y |
| CONVERT_TZ() | Convert from one time zone to another | N |
| CURDATE() | Return the current date | Y |
| CURRENT_DATE() | Synonyms for CURDATE() | Y |
| CURRENT_TIME() | Synonyms for CURTIME() | Y |
| CURRENT_TIMESTAMP() | Synonyms for NOW() | Y |
| CURTIME() | Return the current time | Y |
| DATE() | Extract the date part of a date or datetime expression | Y |
| DATE_ADD() | Add time values (intervals) to a date value | Y |
| DATE_FORMAT() | Format date as specified | Y |
| DATE_SUB() | Subtract a time value (interval) from a date | Y |
| DATEDIFF() | Subtract two dates | Y |
| DAY() | Synonym for DAYOFMONTH() | N |
| DAYNAME() | Return the name of the weekday | Y |
| DAYOFMONTH() | Return the day of the month (0-31) | Y |
| DAYOFWEEK() | Return the weekday index of the argument | Y |
| DAYOFYEAR() | Return the day of the year (1-366) | Y |
| EXTRACT() | Extract part of a date | Y |
| FROM_DAYS() | Convert a day number to a date | Y |
| FROM_UNIXTIME() | Format Unix timestamp as a date | Y |
| GET_FORMAT() | Return a date format string | Y |
| HOUR() | Extract the hour | Y |
| LAST_DAY | Return the last day of the month for the argument | N |
| LOCALTIME() | Synonym for NOW() | Y |
| LOCALTIMESTAMP() | Synonym for NOW() | Y |
| MAKEDATE() | Create a date from the year and day of year | Y |
| MAKETIME() | Create time from hour, minute, second | Y |
| MICROSECOND() | Return the microseconds from argument | Y |
| MINUTE() | Return the minute from the argument | Y |
| MONTH() | Return the month from the date passed | Y |
| MONTHNAME() | Return the name of the month | Y |
| NOW() | Return the current date and time | Y |
| PERIOD_ADD() | Add a period to a year-month | Y |
| PERIOD_DIFF() | Return the number of months between periods | Y |
| QUARTER() | Return the quarter from a date argument | Y |
| SEC_TO_TIME() | Converts seconds to 'HH:MM:SS' format | Y |
| SECOND() | Return the second (0-59) | Y |
| STR_TO_DATE() | Convert a string to a date | Y |
| SUBDATE() | Synonym for DATE_SUB() when invoked with three arguments | Y |
| SUBTIME() | Subtract times | Y |
| SYSDATE() | Return the time at which the function executes | Y |
| TIME() | Extract the time portion of the expression passed | Y |
| TIME_FORMAT() | Format as time | Y |
| TIME_TO_SEC() | Return the argument converted to seconds | Y |
| TIMEDIFF() | Subtract time | Y |
| TIMESTAMP() | With a single argument, this function returns the date or datetime expression; with two arguments, the sum of the arguments | N |
| TIMESTAMPADD() | Add an interval to a datetime expression | Y |
| TIMESTAMPDIFF() | Subtract an interval from a datetime expression | Y |
| TO_DAYS() | Return the date argument converted to days | Y |
| TO_SECONDS() | Return the date or datetime argument converted to seconds since Year 0 | Y |
| UNIX_TIMESTAMP() | Return a Unix timestamp | Y |
| UTC_DATE() | Return the current UTC date | Y |
| UTC_TIME() | Return the current UTC time | Y |
| UTC_TIMESTAMP() | Return the current UTC date and time | Y |
| WEEK() | Return the week number | Y |
| WEEKDAY() | Return the weekday index | Y |
| WEEKOFYEAR() | Return the calendar week of the date (1-53) | Y |
| YEAR() | Return the year | Y |
| YEARWEEK() | Return the year and week | Y |
| CURRENT_DATE | Synonyms for CURDATE() | N |
| CURRENT_TIME | Synonyms for CURTIME() | N |
| CURRENT_TIMESTAMP | Synonyms for NOW() | N |
| LOCALTIME | Synonym for NOW() | N |
| LOCALTIMESTAMP() | Synonym for NOW() | N |
| Name | Description | Support |
|---|---|---|
| BINARY | Cast a string to a binary string | N |
| CAST() | Cast a value as a certain type | Y |
| CONVERT() | Cast a value as a certain type | Y |
BINARY
CHAR[(N)] [charset_info] 包含charset_info时
JSON
SIGNED [INTEGER] 包含INTEGER时(druid解析问题)
UNSIGNED [INTEGER] 包含INTEGER时 (druid解析问题)
BINARY
CHAR[(N)] [charset_info] 包含charset_info时
JSON
SIGNED [INTEGER] 包含INTEGER时(druid解析问题)
UNSIGNED [INTEGER] 包含INTEGER时 (druid解析问题)
| Name | Description | Support |
|---|---|---|
| BIT_COUNT() | Return the number of bits that are set | Y |
| & | Bitwise AND | Y |
| ~ | Bitwise inversion | Y |
| | | Bitwise OR | Y |
| ^ | Bitwise XOR | Y |
| << | Left shift | Y |
| >> | Right shift | Y |
| Name | Description | Support |
|---|---|---|
| AVG() | Return the average value of the argument | Y |
| BIT_AND() | Return bitwise AND | Y |
| BIT_OR() | Return bitwise OR | Y |
| BIT_XOR() | Return bitwise XOR | Y |
| COUNT() | Return a count of the number of rows returned | Y |
| COUNT(DISTINCT) | Return the count of a number of different values | Y |
| GROUP_CONCAT() | Return a concatenated string | Y |
| JSON_ARRAYAGG() | Return result set as a single JSON array | N |
| JSON_OBJECTAGG() | Return result set as a single JSON object | N |
| MAX() | Return the maximum value | Y |
| MIN() | Return the minimum value | Y |
| STD() | Return the population standard deviation | Y |
| STDDEV() | Return the population standard deviation | Y |
| STDDEV_POP() | Return the population standard deviation | Y |
| STDDEV_SAMP() | Return the sample standard deviation | Y |
| SUM() | Return the sum | Y |
| VAR_POP() | Return the population standard variance | Y |
| VAR_SAMP() | Return the sample variance | Y |
| VARIANCE() | Return the population standard variance | Y |
备注:
STD 和VARIANCE相关函数，因为分布式计算的局限性，精度会有一些问题，见 STD()/STDDEV()/STDDEV_POP()/STDDEV_SAMP()/VAR_POP()/VAR_SAMP()/VARIANCE() result precision is not correct
在AVG\SUM等相关计算函数的时候，由于dble的数据来源于MySQL的查询返回，
当MySQL默认返回的数据精度不够时，可能出现最终查询的结果和MySQL的计算结果有少许差异的情况,见
for data type float, dble and mysql may get different results
| Name | Description | Support |
|---|---|---|
| JSON_EXTRACT() | selected from the parts of the json document matched by the path arguments | Y |
| JSON_UNQUOTE() | Unquotes JSON value and returns the result as a utf8mb4 string. | Y |
not supported
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not supported
not supported
not supported
not supported
not supported
not supported