MySQL Common functions

String functions (which are primarily used to process strings):

Cancat (str1, str2, ... strn) connection string str1, str2 ..., strn as a string;

Insert (str, x, Y, instr) starts the string str from position x, and the substring of Y strings is replaced with the string InStr;

LOWER (str) turns all strings in the string str to lowercase;

UPPER (str) turns all strings in the string str to uppercase;

Left (str, x) returns the leftmost x character of the string str;

Right (str, x) returns the rightmost X character of the string str;

Lpad (str, n, pad) uses a string pad to populate the leftmost character of the string str until the length is n string length;

Rpad (str, n, pad) fills the rightmost image of the string str with a string pad until the length is n string length;

LTRIM (str) Removes the left-hand space of the string str;

RTRIM (str) removes the string str to the right of the space;

MySQL Common functions