In MySQL, the LOAD_FILE() function reads a file and returns its contents as a string.
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).