There are two string operators. One uses the string values of the operands and return a string as result. The other one compares the operands and returns a boolean value to indicate match.
String concatenation. The operation returns a text string, that consists of the two operand strings, one after another.
'abc' & 'xyz' returns 'abcxyz'
String comparison with wildcard characters. The operation returns a boolean True (-1) if the string before the operator is matched by the string after the operator. The second string may contain the wildcard characters * (any number of arbitrary characters) or ? (one arbitrary character).
'abc' like 'a*' returns True (-1)
'abcd' like 'a?c*' returns True (-1)
'abc' like 'a??bc' returns False (0)