diff --git a/src/main/java/com/alibaba/druid/sql/dialect/mysql/visitor/MySqlParameterizedOutputVisitor.java b/src/main/java/com/alibaba/druid/sql/dialect/mysql/visitor/MySqlParameterizedOutputVisitor.java
index bec84a1030..c3fef1d96e 100644
--- a/src/main/java/com/alibaba/druid/sql/dialect/mysql/visitor/MySqlParameterizedOutputVisitor.java
+++ b/src/main/java/com/alibaba/druid/sql/dialect/mysql/visitor/MySqlParameterizedOutputVisitor.java
@@ -8,6 +8,7 @@ import com.alibaba.druid.sql.ast.expr.SQLInListExpr;
 import com.alibaba.druid.sql.ast.expr.SQLIntegerExpr;
 import com.alibaba.druid.sql.ast.expr.SQLLiteralExpr;
 import com.alibaba.druid.sql.ast.expr.SQLNCharExpr;
+import com.alibaba.druid.sql.ast.expr.SQLNullExpr;
 import com.alibaba.druid.sql.ast.expr.SQLNumberExpr;
 import com.alibaba.druid.sql.ast.expr.SQLVariantRefExpr;
 import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlInsertStatement;
@@ -41,6 +42,11 @@ public class MySqlParameterizedOutputVisitor extends MySqlOutputVisitor {
 
         return super.visit(x);
     }
+    
+    public boolean visit(SQLNullExpr x) {
+        print('?');
+        return false;
+    }
 
     public SQLBinaryOpExpr merge(SQLBinaryOpExpr x) {
         if (x.getLeft() instanceof SQLLiteralExpr && x.getRight() instanceof SQLLiteralExpr) {
diff --git a/src/main/java/com/alibaba/druid/sql/dialect/oracle/visitor/OracleParameterizedOutputVisitor.java b/src/main/java/com/alibaba/druid/sql/dialect/oracle/visitor/OracleParameterizedOutputVisitor.java
index 6af26d06cf..d3482dd18d 100644
--- a/src/main/java/com/alibaba/druid/sql/dialect/oracle/visitor/OracleParameterizedOutputVisitor.java
+++ b/src/main/java/com/alibaba/druid/sql/dialect/oracle/visitor/OracleParameterizedOutputVisitor.java
@@ -8,6 +8,7 @@ import com.alibaba.druid.sql.ast.expr.SQLInListExpr;
 import com.alibaba.druid.sql.ast.expr.SQLIntegerExpr;
 import com.alibaba.druid.sql.ast.expr.SQLLiteralExpr;
 import com.alibaba.druid.sql.ast.expr.SQLNCharExpr;
+import com.alibaba.druid.sql.ast.expr.SQLNullExpr;
 import com.alibaba.druid.sql.ast.expr.SQLNumberExpr;
 import com.alibaba.druid.sql.ast.expr.SQLVariantRefExpr;
 
@@ -40,6 +41,11 @@ public class OracleParameterizedOutputVisitor extends OracleOutputVisitor {
 
         return super.visit(x);
     }
+    
+    public boolean visit(SQLNullExpr x) {
+        print('?');
+        return false;
+    }
 
     public SQLBinaryOpExpr merge(SQLBinaryOpExpr x) {
         if (x.getLeft() instanceof SQLLiteralExpr && x.getRight() instanceof SQLLiteralExpr) {