improve sql-wal

src/main/java/com/alibaba/druid/sql/dialect/db2/visitor/DB2EvalVisitor.java

@@ -135,7 +135,7 @@ public class DB2EvalVisitor extends DB2ASTVisitorAdapter implements SQLEvalVisit
     public void registerFunction(String funcName, Function function) {
         functions.put(funcName, function);
     }
-    
+
     public boolean visit(SQLIdentifierExpr x) {
         return SQLEvalVisitorUtils.visit(this, x);
     }

src/main/java/com/alibaba/druid/sql/dialect/mysql/parser/MySqlExprParser.java

@@ -558,12 +558,6 @@ public class MySqlExprParser extends SQLExprParser {
             throw new ParserException("syntax error " + lexer.token() + " " + lexer.stringVal());
         }
 
-        if (lexer.token() == Token.COMMENT) {
-            lexer.nextToken();
-            column.setComment(lexer.stringVal());
-            accept(Token.LITERAL_CHARS);
-        }
-
         if (identifierEquals("STORAGE")) {
             lexer.nextToken();
             SQLExpr expr = expr();
@@ -727,7 +721,7 @@ public class MySqlExprParser extends SQLExprParser {
         if (lexer.token() == Token.KEY) {
             lexer.nextToken();
         }
-        
+
         if (lexer.token() == Token.INDEX) {
             lexer.nextToken();
         }

src/main/java/com/alibaba/druid/sql/dialect/mysql/visitor/MySqlEvalVisitorImpl.java

@@ -24,6 +24,7 @@ import com.alibaba.druid.sql.ast.expr.SQLBetweenExpr;
 import com.alibaba.druid.sql.ast.expr.SQLBinaryOpExpr;
 import com.alibaba.druid.sql.ast.expr.SQLCaseExpr;
 import com.alibaba.druid.sql.ast.expr.SQLCharExpr;
+import com.alibaba.druid.sql.ast.expr.SQLHexExpr;
 import com.alibaba.druid.sql.ast.expr.SQLIdentifierExpr;
 import com.alibaba.druid.sql.ast.expr.SQLInListExpr;
 import com.alibaba.druid.sql.ast.expr.SQLIntegerExpr;
@@ -33,6 +34,7 @@ import com.alibaba.druid.sql.ast.expr.SQLNumberExpr;
 import com.alibaba.druid.sql.ast.expr.SQLQueryExpr;
 import com.alibaba.druid.sql.ast.expr.SQLUnaryExpr;
 import com.alibaba.druid.sql.ast.expr.SQLVariantRefExpr;
+import com.alibaba.druid.sql.dialect.mysql.ast.expr.MySqlBinaryExpr;
 import com.alibaba.druid.sql.dialect.mysql.ast.expr.MySqlBooleanExpr;
 import com.alibaba.druid.sql.visitor.SQLEvalVisitor;
 import com.alibaba.druid.sql.visitor.SQLEvalVisitorUtils;
@@ -94,6 +96,14 @@ public class MySqlEvalVisitorImpl extends MySqlASTVisitorAdapter implements SQLE
     public boolean visit(SQLNumberExpr x) {
         return SQLEvalVisitorUtils.visit(this, x);
     }
+    
+    public boolean visit(SQLHexExpr x) {
+        return SQLEvalVisitorUtils.visit(this, x);
+    }
+    
+    public boolean visit(MySqlBinaryExpr x) {
+        return SQLEvalVisitorUtils.visit(this, x);
+    }
 
     @Override
     public boolean visit(SQLCaseExpr x) {

src/main/java/com/alibaba/druid/sql/dialect/mysql/visitor/MySqlOutputVisitor.java

@@ -324,6 +324,11 @@ public class MySqlOutputVisitor extends SQLASTOutputVisitor implements MySqlASTV
             print(' ');
             item.accept(this);
         }
+        
+        if (x.getComment() != null) {
+            print(" COMMENT ");
+            x.getComment().accept(this);
+        }
 
         return false;
     }

src/main/java/com/alibaba/druid/sql/dialect/oracle/visitor/OracleEvalVisitor.java

@@ -135,7 +135,7 @@ public class OracleEvalVisitor extends OracleASTVisitorAdapter implements SQLEva
     public void registerFunction(String funcName, Function function) {
         functions.put(funcName, function);
     }
-    
+
     public boolean visit(SQLIdentifierExpr x) {
         return SQLEvalVisitorUtils.visit(this, x);
     }

src/main/java/com/alibaba/druid/sql/dialect/postgresql/visitor/PGEvalVisitor.java

@@ -135,7 +135,7 @@ public class PGEvalVisitor extends PGASTVisitorAdapter implements SQLEvalVisitor
     public void registerFunction(String funcName, Function function) {
         functions.put(funcName, function);
     }
-    
+
     public boolean visit(SQLIdentifierExpr x) {
         return SQLEvalVisitorUtils.visit(this, x);
     }

src/main/java/com/alibaba/druid/sql/dialect/sqlserver/visitor/SQLServerEvalVisitor.java

@@ -92,7 +92,7 @@ public class SQLServerEvalVisitor extends SQLServerASTVisitorAdapter implements
     public boolean visit(SQLNumberExpr x) {
         return SQLEvalVisitorUtils.visit(this, x);
     }
-
+    
     @Override
     public boolean visit(SQLCaseExpr x) {
         return SQLEvalVisitorUtils.visit(this, x);