A string function that repeats a string a specified number of times.
Description
REPEAT returns a string of repeat-count instances of expression, concatenated together.
If expression is NULL, REPEAT returns NULL. If expression is the empty string, REPEAT returns an empty string.
If repeat-count is a fractional number, only the integer part is used. If repeat-count is 0, REPEAT returns an empty string. If repeat-count is a negative number, NULL, or a non-numeric string, REPEAT returns NULL.