diff --git a/common/core/src/main/java/zingg/common/core/hash/IdentityDate.java b/common/core/src/main/java/zingg/common/core/hash/IdentityDate.java
new file mode 100644
index 000000000..a0150a844
--- /dev/null
+++ b/common/core/src/main/java/zingg/common/core/hash/IdentityDate.java
@@ -0,0 +1,20 @@
+package zingg.common.core.hash;
+import java.util.Date;
+import java.time.LocalDate;
+public class IdentityDate extends BaseHash<Date, Integer> {
+
+    public IdentityDate() {
+        setName("identityDate");
+    }
+
+    @Override
+    public Integer call(Date date) {
+        if(date == null) {
+            return null;
+        }
+        int year = date.getYear() + 1900;
+        int month = date.getMonth() + 1;
+        int day = date.getDate();
+        return year * 10000 + month * 100 + day;
+    }
+}
diff --git a/common/core/src/main/java/zingg/common/core/hash/SameMonthYear.java b/common/core/src/main/java/zingg/common/core/hash/SameMonthYear.java
new file mode 100644
index 000000000..3fa2e211f
--- /dev/null
+++ b/common/core/src/main/java/zingg/common/core/hash/SameMonthYear.java
@@ -0,0 +1,19 @@
+package zingg.common.core.hash;
+
+import java.util.Date;
+
+public class SameMonthYear extends BaseHash<Date, Integer>{
+    public SameMonthYear() {
+        setName("sameMonthYear");
+    }
+
+    @Override
+    public Integer call(Date date) {
+        if(date == null) {
+            return null;
+        }
+        int year = date.getYear() + 1900;
+        int month = date.getMonth() + 1;
+        return year * 100 + month;
+    }
+}
diff --git a/common/core/src/test/java/zingg/hash/TestIdentityDate.java b/common/core/src/test/java/zingg/hash/TestIdentityDate.java
new file mode 100644
index 000000000..a30c2d31e
--- /dev/null
+++ b/common/core/src/test/java/zingg/hash/TestIdentityDate.java
@@ -0,0 +1,28 @@
+package zingg.hash;
+
+import org.junit.jupiter.api.Test;
+import zingg.common.core.hash.IdentityDate;
+import zingg.common.core.hash.IdentityInteger;
+
+import java.util.Date;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class TestIdentityDate {
+
+    @Test
+    public void testIdentityInteger() {
+        IdentityDate value = getInstance();
+        assertEquals(20020624, value.call(new Date("2002/06/24")));
+    }
+
+    @Test
+    public void testNullValue() {
+        IdentityDate value = getInstance();
+        assertEquals(null, value.call(null));
+    }
+
+    private IdentityDate getInstance() {
+        return new IdentityDate();
+    }
+}
diff --git a/common/core/src/test/java/zingg/hash/TestSameMonthYear.java b/common/core/src/test/java/zingg/hash/TestSameMonthYear.java
new file mode 100644
index 000000000..db60ff4f2
--- /dev/null
+++ b/common/core/src/test/java/zingg/hash/TestSameMonthYear.java
@@ -0,0 +1,34 @@
+package zingg.hash;
+
+import java.util.Date;
+import org.junit.jupiter.api.Test;
+import zingg.common.core.hash.SameMonthYear;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class TestSameMonthYear {
+    @Test
+    public void testSameMonthYear() {
+        SameMonthYear value = getInstance();
+        assertEquals(200206, value.call(new Date("2002/06/24")));
+    }
+
+    @Test
+    public void testSameMonthYear2() {
+        SameMonthYear value = getInstance();
+        assertEquals(value.call(new Date("2002/06/11")),
+                    value.call(new Date("2002/06/24")));
+    }
+
+    @Test
+    public void testNullValue() {
+        SameMonthYear value = getInstance();
+        assertEquals(null, value.call(null));
+    }
+
+    private SameMonthYear getInstance() {
+        return new SameMonthYear();
+    }
+
+
+}
diff --git a/spark/core/src/main/java/zingg/spark/core/hash/SparkSameMonthYear.java b/spark/core/src/main/java/zingg/spark/core/hash/SparkSameMonthYear.java
new file mode 100644
index 000000000..936831bf1
--- /dev/null
+++ b/spark/core/src/main/java/zingg/spark/core/hash/SparkSameMonthYear.java
@@ -0,0 +1,15 @@
+package zingg.spark.core.hash;
+
+import org.apache.spark.sql.types.DataTypes;
+import zingg.common.core.hash.SameMonthYear;
+
+import java.util.Date;
+
+public class SparkSameMonthYear extends SparkHashFunction<Date, Integer> {
+    public SparkSameMonthYear() {
+        setBaseHash(new SameMonthYear());
+        setDataType(DataTypes.DateType);
+        setReturnType(DataTypes.IntegerType);
+    }
+}
+