Tests for the presence of a specified string anywhere inside
    a string expression. A conditional expression that includes a
    CONTAINING clause is true if the string specified by the second
    (pattern) string expression is found within the string specified
    by the first (target) string expression. If either of the string
    expressions in a CONTAINING conditional expression is missing,
    the result is missing.

    If you precede the CONTAINING clause with the optional NOT
    qualifier, the condition is true if there are no records
    containing the specified string. CONTAINING is not case
    sensitive; it considers uppercase and lowercase forms of the
    same character to be a match.