In MySQL, the LEFT() function returns the leftmost characters from a string. The number of characters returned is determined by the second argument.
string functions
How the UCASE() Function Works in MySQL
In MySQL, the UCASE() function is a synonym for UPPER(). In other words, you can use either of these functions to do the same thing.
Specifically, both functions convert lowercase characters to uppercase (and return the result), according to the current character set mapping (the default mapping is utf8mb4).
How the INSTR() Function Works in MySQL
The INSTR() function returns the position of the first occurrence of a substring within a string. Basically, it does the same thing that the two-argument syntax of the LOCATE() function does (except that the order of the arguments is reversed).
How the EXPORT_SET() Function Works in MySQL
The MySQL EXPORT_SET() function returns a string that represents the bits in a number.
You have the ability to customise how the function outputs the string. The function accepts a number of arguments that allows you to do this. When you call the function, you provide the number in question, as well as arguments that determine how the results are displayed.