improved sql parser.

src/main/java/com/alibaba/druid/sql/parser/Lexer.java

@@ -582,7 +582,12 @@ public class Lexer {
                 break;
             case '^':
                 scanChar();
-                token = Token.CARET;
+                if (ch == '=') {
+                    scanChar();
+                    token = Token.CARETEQ;
+                } else {
+                    token = Token.CARET;
+                }
                 break;
             case '%':
                 scanChar();

src/main/java/com/alibaba/druid/sql/parser/Token.java

@@ -334,7 +334,8 @@ public enum Token {
     SLASH("/"), 
     AMP("&"), 
     BAR("|"), 
-    CARET("^"), 
+    CARET("^"),
+    CARETEQ("^="),
     PERCENT("%"), 
     LTLT("<<"), 
     GTGT(">>"),