| lower(column str) |
String to lowercase |
| upper(column str) |
Convert string to uppercase |
| concat(column str， column str, …) |
Concatenated string |
| concat_ws(separator, column str, column str, …), |
Specified splicing character splicing string |
| substr(str, pos[, length]) |
Returns a substring of the string, pos index starts from 1, and length is not specified to the end |
| substring(str, pos[, length]) |
Same as above, index starts from 1 |
| left(str, length) |
Intercept the substring of the specified length on the left |
| right(str, length) |
Intercept the substring of the specified length on the right |
| length(str) |
Get the byte length of a string |
| char_length(str) |
Character length of the string |
| instr(str, substr) |
Returns the index position of the substring in the string, if not found, it returns 0 |
| lpad(str, length, padstr) |
Left padding |
| rpad(str, length, padstr) |
Right fill |
| trim( [substr from] str ) |
Remove the specified substring at the beginning and end of the string, the default substring is a space |
| ltrim([substr from] str) |
Remove the specified substring on the left side of the string, the default substring is a space |
| rtrim([substr from] str) |
Remove the specified substring on the right side of the string, the default substring is a space |
| replace(str, from_str, to_str) |
Replace all matched substrings |
| format(x , D[, local]) |
Format the number x, which can be used to intercept the number of decimal places, round up, etc. |
| space(N) |
Return a substring consisting of N spaces |
| repeat(str, count) |
Return a string composed of repeated string count times |
| reverse(str) |
Reverse string |
| strcmp( str1, str2 ) |
Compare two strings, greater than return 1; equal to return 0; less than return -1 |