字符串函数
更新时间：2024-02-23
GaiaDB-X 支持的函数，如下：
| 函数名 | 描述 |
|---|---|
| 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() | Index (position) of first argument in subsequent arguments |
| FORMAT() | Return a number formatted to specified number of decimal places |
| FROM_BASE64() | Decode base64 encoded string and return result |
| HEX() | Hexadecimal representation of decimal or string value |
| INSERT() | Insert substring at specified position up to 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 |
| 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 |
| 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 | Whether string matches regular expression |
| 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 | Whether string matches regular expression |
| RPAD() | Append string the specified number of times |
| RTRIM() | Remove trailing spaces |
| SOUNDEX() | Return a soundex string |
| 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 |
相比MySQL5.7，GaiaDB-X 暂不支持的函数，如下
| 函数名 | 描述 |
|---|---|
| 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 |