Letters and underscore detected in a LIKE string Explanation: The converter converts MATCHING string constants to use the LIKE wildcard characters. There is no way to have both letters and an underscore in a LIKE target string that will still have the same semantics as the original, because SQL only permits either IGNORE CASE or an ESCAPE character, but not both. The converter will generate IGNORE CASE andthe underscore will act as a wild card, matching ANY single character (as '%' does in MATCHING. User Action: Change the target pattern.