diff --git a/src/main/java/com/alibaba/druid/sql/ast/expr/SQLBinaryOpExpr.java b/src/main/java/com/alibaba/druid/sql/ast/expr/SQLBinaryOpExpr.java
index f39e8bdef1..42d3e31472 100644
--- a/src/main/java/com/alibaba/druid/sql/ast/expr/SQLBinaryOpExpr.java
+++ b/src/main/java/com/alibaba/druid/sql/ast/expr/SQLBinaryOpExpr.java
@@ -86,4 +86,48 @@ public class SQLBinaryOpExpr extends SQLExprImpl implements Serializable {
 
         visitor.endVisit(this);
     }
+
+    @Override
+    public int hashCode() {
+        final int prime = 31;
+        int result = 1;
+        result = prime * result + ((left == null) ? 0 : left.hashCode());
+        result = prime * result + ((operator == null) ? 0 : operator.hashCode());
+        result = prime * result + ((right == null) ? 0 : right.hashCode());
+        return result;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj == null) {
+            return false;
+        }
+        if (!(obj instanceof SQLBinaryOpExpr)) {
+            return false;
+        }
+        SQLBinaryOpExpr other = (SQLBinaryOpExpr) obj;
+        if (left == null) {
+            if (other.left != null) {
+                return false;
+            }
+        } else if (!left.equals(other.left)) {
+            return false;
+        }
+        if (operator != other.operator) {
+            return false;
+        }
+        if (right == null) {
+            if (other.right != null) {
+                return false;
+            }
+        } else if (!right.equals(other.right)) {
+            return false;
+        }
+        return true;
+    }
+    
+    
 }
diff --git a/src/main/java/com/alibaba/druid/sql/ast/expr/SQLIdentifierExpr.java b/src/main/java/com/alibaba/druid/sql/ast/expr/SQLIdentifierExpr.java
index a60e18274f..fb8d29f0e9 100644
--- a/src/main/java/com/alibaba/druid/sql/ast/expr/SQLIdentifierExpr.java
+++ b/src/main/java/com/alibaba/druid/sql/ast/expr/SQLIdentifierExpr.java
@@ -51,4 +51,36 @@ public class SQLIdentifierExpr extends SQLExprImpl implements SQLName {
 
         visitor.endVisit(this);
     }
+
+    @Override
+    public int hashCode() {
+        final int prime = 31;
+        int result = 1;
+        result = prime * result + ((name == null) ? 0 : name.hashCode());
+        return result;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj == null) {
+            return false;
+        }
+        if (!(obj instanceof SQLIdentifierExpr)) {
+            return false;
+        }
+        SQLIdentifierExpr other = (SQLIdentifierExpr) obj;
+        if (name == null) {
+            if (other.name != null) {
+                return false;
+            }
+        } else if (!name.equals(other.name)) {
+            return false;
+        }
+        return true;
+    }
+    
+    
 }
diff --git a/src/main/java/com/alibaba/druid/sql/ast/expr/SQLPropertyExpr.java b/src/main/java/com/alibaba/druid/sql/ast/expr/SQLPropertyExpr.java
index c372a9b961..ae1776e4b9 100644
--- a/src/main/java/com/alibaba/druid/sql/ast/expr/SQLPropertyExpr.java
+++ b/src/main/java/com/alibaba/druid/sql/ast/expr/SQLPropertyExpr.java
@@ -66,4 +66,44 @@ public class SQLPropertyExpr extends SQLExprImpl implements SQLName {
 
         visitor.endVisit(this);
     }
+
+    @Override
+    public int hashCode() {
+        final int prime = 31;
+        int result = 1;
+        result = prime * result + ((name == null) ? 0 : name.hashCode());
+        result = prime * result + ((owner == null) ? 0 : owner.hashCode());
+        return result;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj == null) {
+            return false;
+        }
+        if (!(obj instanceof SQLPropertyExpr)) {
+            return false;
+        }
+        SQLPropertyExpr other = (SQLPropertyExpr) obj;
+        if (name == null) {
+            if (other.name != null) {
+                return false;
+            }
+        } else if (!name.equals(other.name)) {
+            return false;
+        }
+        if (owner == null) {
+            if (other.owner != null) {
+                return false;
+            }
+        } else if (!owner.equals(other.owner)) {
+            return false;
+        }
+        return true;
+    }
+    
+    
 }
diff --git a/src/main/java/com/alibaba/druid/sql/ast/expr/SQLVariantRefExpr.java b/src/main/java/com/alibaba/druid/sql/ast/expr/SQLVariantRefExpr.java
index c5992eaa5a..030d2b1e65 100644
--- a/src/main/java/com/alibaba/druid/sql/ast/expr/SQLVariantRefExpr.java
+++ b/src/main/java/com/alibaba/druid/sql/ast/expr/SQLVariantRefExpr.java
@@ -51,4 +51,36 @@ public class SQLVariantRefExpr extends SQLExprImpl {
 
         visitor.endVisit(this);
     }
+
+    @Override
+    public int hashCode() {
+        final int prime = 31;
+        int result = 1;
+        result = prime * result + ((name == null) ? 0 : name.hashCode());
+        return result;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj == null) {
+            return false;
+        }
+        if (!(obj instanceof SQLVariantRefExpr)) {
+            return false;
+        }
+        SQLVariantRefExpr other = (SQLVariantRefExpr) obj;
+        if (name == null) {
+            if (other.name != null) {
+                return false;
+            }
+        } else if (!name.equals(other.name)) {
+            return false;
+        }
+        return true;
+    }
+    
+    
 }
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 c3fef1d96e..953c2578ff 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
@@ -42,7 +42,7 @@ public class MySqlParameterizedOutputVisitor extends MySqlOutputVisitor {
 
         return super.visit(x);
     }
-    
+
     public boolean visit(SQLNullExpr x) {
         print('?');
         return false;
@@ -65,8 +65,19 @@ public class MySqlParameterizedOutputVisitor extends MySqlOutputVisitor {
             x = new SQLBinaryOpExpr(new SQLVariantRefExpr("?"), x.getOperator(), x.getRight());
         }
 
-        if (x.getRight() instanceof SQLBinaryOpExpr) {
-            x = new SQLBinaryOpExpr(x.getLeft(), x.getOperator(), merge((SQLBinaryOpExpr) x.getRight()));
+        for (;;) {
+            if (x.getRight() instanceof SQLBinaryOpExpr) {
+                if (x.getLeft() instanceof SQLBinaryOpExpr) {
+                    SQLBinaryOpExpr leftBinaryExpr = (SQLBinaryOpExpr) x.getLeft();
+                    if (leftBinaryExpr.getRight().equals(x.getRight())) {
+                        x = leftBinaryExpr;
+                        continue;
+                    }
+                }
+                x = new SQLBinaryOpExpr(x.getLeft(), x.getOperator(), merge((SQLBinaryOpExpr) x.getRight()));
+            }
+            
+            break;
         }
 
         if (x.getLeft() instanceof SQLBinaryOpExpr) {
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 d3482dd18d..3e3273b9e7 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
@@ -64,8 +64,19 @@ public class OracleParameterizedOutputVisitor extends OracleOutputVisitor {
             x = new SQLBinaryOpExpr(new SQLVariantRefExpr("?"), x.getOperator(), x.getRight());
         }
 
-        if (x.getRight() instanceof SQLBinaryOpExpr) {
-            x = new SQLBinaryOpExpr(x.getLeft(), x.getOperator(), merge((SQLBinaryOpExpr) x.getRight()));
+        for (;;) {
+            if (x.getRight() instanceof SQLBinaryOpExpr) {
+                if (x.getLeft() instanceof SQLBinaryOpExpr) {
+                    SQLBinaryOpExpr leftBinaryExpr = (SQLBinaryOpExpr) x.getLeft();
+                    if (leftBinaryExpr.getRight().equals(x.getRight())) {
+                        x = leftBinaryExpr;
+                        continue;
+                    }
+                }
+                x = new SQLBinaryOpExpr(x.getLeft(), x.getOperator(), merge((SQLBinaryOpExpr) x.getRight()));
+            }
+            
+            break;
         }
 
         if (x.getLeft() instanceof SQLBinaryOpExpr) {