refactor

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

@@ -725,6 +725,7 @@ public class MySqlOutputVisitor extends SQLASTOutputVisitor implements MySqlASTV
         x.getTableName().accept(this);
 
         if (x.getColumns().size() > 0) {
+            incrementIndent();
             println();
             print("(");
             for (int i = 0, size = x.getColumns().size(); i < size; ++i) {
@@ -738,6 +739,7 @@ public class MySqlOutputVisitor extends SQLASTOutputVisitor implements MySqlASTV
                 x.getColumns().get(i).accept(this);
             }
             print(")");
+            decrementIndent();
         }
 
         if (x.getValuesList().size() != 0) {

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

@@ -21,10 +21,6 @@ public class MySqlParameterizedOutputVisitor extends MySqlOutputVisitor {
         super(appender);
     }
 
-    public void println() {
-        print(' ');
-    }
-
     public boolean visit(SQLInListExpr x) {
         x.getExpr().accept(this);