diff --git a/mybatis-plus-join-core/src/main/java/com/github/yulichang/interfaces/MPJBaseJoin.java b/mybatis-plus-join-core/src/main/java/com/github/yulichang/interfaces/MPJBaseJoin.java
index 2fbf71e..aeb1ba2 100644
--- a/mybatis-plus-join-core/src/main/java/com/github/yulichang/interfaces/MPJBaseJoin.java
+++ b/mybatis-plus-join-core/src/main/java/com/github/yulichang/interfaces/MPJBaseJoin.java
@@ -15,4 +15,8 @@ public interface MPJBaseJoin<T> {
     default String getDeleteLogicSql() {
         return StringPool.EMPTY;
     }
+
+    default String getUnionSql(){
+        return StringPool.EMPTY;
+    }
 }
diff --git a/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/SelectJoinList.java b/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/SelectJoinList.java
index 3667c3f..f18ca33 100644
--- a/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/SelectJoinList.java
+++ b/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/SelectJoinList.java
@@ -1,6 +1,10 @@
 package com.github.yulichang.method;
 
 import com.baomidou.mybatisplus.core.metadata.TableInfo;
+import com.baomidou.mybatisplus.core.toolkit.Constants;
+import com.baomidou.mybatisplus.core.toolkit.StringPool;
+import com.baomidou.mybatisplus.core.toolkit.sql.SqlScriptUtils;
+import com.github.yulichang.interfaces.MPJBaseJoin;
 import org.apache.ibatis.mapping.MappedStatement;
 import org.apache.ibatis.mapping.SqlSource;
 
@@ -30,4 +34,10 @@ public class SelectJoinList extends MPJAbstractMethod {
         SqlSource sqlSource = languageDriver.createSqlSource(configuration, sql, modelClass);
         return this.addSelectMappedStatementForOther(mapperClass, sqlMethod.getMethod(), sqlSource, MPJResultType.class);
     }
+
+    @Override
+    protected String sqlComment() {
+        return super.sqlComment() + StringPool.NEWLINE + SqlScriptUtils.convertIf("${ew.unionSql}", String.format("%s != null and (%s instanceof %s)",
+                Constants.WRAPPER, Constants.WRAPPER, MPJBaseJoin.class.getName()), true);
+    }
 }
diff --git a/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/SelectJoinMap.java b/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/SelectJoinMap.java
index 2951078..74fd719 100644
--- a/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/SelectJoinMap.java
+++ b/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/SelectJoinMap.java
@@ -1,6 +1,10 @@
 package com.github.yulichang.method;
 
 import com.baomidou.mybatisplus.core.metadata.TableInfo;
+import com.baomidou.mybatisplus.core.toolkit.Constants;
+import com.baomidou.mybatisplus.core.toolkit.StringPool;
+import com.baomidou.mybatisplus.core.toolkit.sql.SqlScriptUtils;
+import com.github.yulichang.interfaces.MPJBaseJoin;
 import org.apache.ibatis.mapping.MappedStatement;
 import org.apache.ibatis.mapping.SqlSource;
 
@@ -31,4 +35,10 @@ public class SelectJoinMap extends MPJAbstractMethod {
         SqlSource sqlSource = languageDriver.createSqlSource(configuration, sql, modelClass);
         return this.addSelectMappedStatementForOther(mapperClass, sqlMethod.getMethod(), sqlSource, Map.class);
     }
+
+    @Override
+    protected String sqlComment() {
+        return super.sqlComment() + StringPool.NEWLINE + SqlScriptUtils.convertIf("${ew.unionSql}", String.format("%s != null and (%s instanceof %s)",
+                Constants.WRAPPER, Constants.WRAPPER, MPJBaseJoin.class.getName()), true);
+    }
 }
diff --git a/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/SelectJoinMaps.java b/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/SelectJoinMaps.java
index 8e0c67a..7db4c14 100644
--- a/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/SelectJoinMaps.java
+++ b/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/SelectJoinMaps.java
@@ -1,6 +1,10 @@
 package com.github.yulichang.method;
 
 import com.baomidou.mybatisplus.core.metadata.TableInfo;
+import com.baomidou.mybatisplus.core.toolkit.Constants;
+import com.baomidou.mybatisplus.core.toolkit.StringPool;
+import com.baomidou.mybatisplus.core.toolkit.sql.SqlScriptUtils;
+import com.github.yulichang.interfaces.MPJBaseJoin;
 import org.apache.ibatis.mapping.MappedStatement;
 import org.apache.ibatis.mapping.SqlSource;
 
@@ -32,4 +36,10 @@ public class SelectJoinMaps extends MPJAbstractMethod {
         SqlSource sqlSource = languageDriver.createSqlSource(configuration, sql, modelClass);
         return this.addSelectMappedStatementForOther(mapperClass, sqlMethod.getMethod(), sqlSource, Map.class);
     }
+
+    @Override
+    protected String sqlComment() {
+        return super.sqlComment() + StringPool.NEWLINE + SqlScriptUtils.convertIf("${ew.unionSql}", String.format("%s != null and (%s instanceof %s)",
+                Constants.WRAPPER, Constants.WRAPPER, MPJBaseJoin.class.getName()), true);
+    }
 }
diff --git a/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/SelectJoinMapsPage.java b/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/SelectJoinMapsPage.java
index 2c4169c..da609a2 100644
--- a/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/SelectJoinMapsPage.java
+++ b/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/SelectJoinMapsPage.java
@@ -1,6 +1,10 @@
 package com.github.yulichang.method;
 
 import com.baomidou.mybatisplus.core.metadata.TableInfo;
+import com.baomidou.mybatisplus.core.toolkit.Constants;
+import com.baomidou.mybatisplus.core.toolkit.StringPool;
+import com.baomidou.mybatisplus.core.toolkit.sql.SqlScriptUtils;
+import com.github.yulichang.interfaces.MPJBaseJoin;
 import org.apache.ibatis.mapping.MappedStatement;
 import org.apache.ibatis.mapping.SqlSource;
 
@@ -32,4 +36,10 @@ public class SelectJoinMapsPage extends MPJAbstractMethod {
         SqlSource sqlSource = languageDriver.createSqlSource(configuration, sql, modelClass);
         return this.addSelectMappedStatementForOther(mapperClass, sqlMethod.getMethod(), sqlSource, Map.class);
     }
+
+    @Override
+    protected String sqlComment() {
+        return super.sqlComment() + StringPool.NEWLINE + SqlScriptUtils.convertIf("${ew.unionSql}", String.format("%s != null and (%s instanceof %s)",
+                Constants.WRAPPER, Constants.WRAPPER, MPJBaseJoin.class.getName()), true);
+    }
 }
diff --git a/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/SelectJoinOne.java b/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/SelectJoinOne.java
index 596c076..3ded876 100644
--- a/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/SelectJoinOne.java
+++ b/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/SelectJoinOne.java
@@ -1,6 +1,10 @@
 package com.github.yulichang.method;
 
 import com.baomidou.mybatisplus.core.metadata.TableInfo;
+import com.baomidou.mybatisplus.core.toolkit.Constants;
+import com.baomidou.mybatisplus.core.toolkit.StringPool;
+import com.baomidou.mybatisplus.core.toolkit.sql.SqlScriptUtils;
+import com.github.yulichang.interfaces.MPJBaseJoin;
 import org.apache.ibatis.mapping.MappedStatement;
 import org.apache.ibatis.mapping.SqlSource;
 
@@ -29,4 +33,10 @@ public class SelectJoinOne extends MPJAbstractMethod {
         SqlSource sqlSource = languageDriver.createSqlSource(configuration, sql, modelClass);
         return this.addSelectMappedStatementForOther(mapperClass, sqlMethod.getMethod(), sqlSource, MPJResultType.class);
     }
+
+    @Override
+    protected String sqlComment() {
+        return super.sqlComment() + StringPool.NEWLINE + SqlScriptUtils.convertIf("${ew.unionSql}", String.format("%s != null and (%s instanceof %s)",
+                Constants.WRAPPER, Constants.WRAPPER, MPJBaseJoin.class.getName()), true);
+    }
 }
diff --git a/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/SelectJoinPage.java b/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/SelectJoinPage.java
index f3b3d2a..49a512a 100644
--- a/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/SelectJoinPage.java
+++ b/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/SelectJoinPage.java
@@ -1,6 +1,10 @@
 package com.github.yulichang.method;
 
 import com.baomidou.mybatisplus.core.metadata.TableInfo;
+import com.baomidou.mybatisplus.core.toolkit.Constants;
+import com.baomidou.mybatisplus.core.toolkit.StringPool;
+import com.baomidou.mybatisplus.core.toolkit.sql.SqlScriptUtils;
+import com.github.yulichang.interfaces.MPJBaseJoin;
 import org.apache.ibatis.mapping.MappedStatement;
 import org.apache.ibatis.mapping.SqlSource;
 
@@ -30,4 +34,10 @@ public class SelectJoinPage extends MPJAbstractMethod {
         SqlSource sqlSource = languageDriver.createSqlSource(configuration, sql, modelClass);
         return this.addSelectMappedStatementForOther(mapperClass, sqlMethod.getMethod(), sqlSource, MPJResultType.class);
     }
+
+    @Override
+    protected String sqlComment() {
+        return super.sqlComment() + StringPool.NEWLINE + SqlScriptUtils.convertIf("${ew.unionSql}", String.format("%s != null and (%s instanceof %s)",
+                Constants.WRAPPER, Constants.WRAPPER, MPJBaseJoin.class.getName()), true);
+    }
 }
diff --git a/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/mp/SelectList.java b/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/mp/SelectList.java
index fb6cc63..90233ff 100644
--- a/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/mp/SelectList.java
+++ b/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/mp/SelectList.java
@@ -45,4 +45,10 @@ public class SelectList extends com.baomidou.mybatisplus.core.injector.methods.S
         return SqlScriptUtils.convertChoose(String.format("%s == null or !(%s instanceof %s)", Constants.WRAPPER, Constants.WRAPPER, MPJBaseJoin.class.getName()),
                 selectColumns, mpjSqlSelectColumns() + StringPool.SPACE + selectColumns);
     }
+
+    @Override
+    protected String sqlComment() {
+        return super.sqlComment() + StringPool.NEWLINE + SqlScriptUtils.convertIf("${ew.unionSql}", String.format("%s != null and (%s instanceof %s)",
+                Constants.WRAPPER, Constants.WRAPPER, MPJBaseJoin.class.getName()), true);
+    }
 }
diff --git a/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/mp/SelectMaps.java b/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/mp/SelectMaps.java
index 2485317..3b3a312 100644
--- a/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/mp/SelectMaps.java
+++ b/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/mp/SelectMaps.java
@@ -45,4 +45,10 @@ public class SelectMaps extends com.baomidou.mybatisplus.core.injector.methods.S
         return SqlScriptUtils.convertChoose(String.format("%s == null or !(%s instanceof %s)", Constants.WRAPPER, Constants.WRAPPER, MPJBaseJoin.class.getName()),
                 selectColumns, mpjSqlSelectColumns() + StringPool.SPACE + selectColumns);
     }
+
+    @Override
+    protected String sqlComment() {
+        return super.sqlComment() + StringPool.NEWLINE + SqlScriptUtils.convertIf("${ew.unionSql}", String.format("%s != null and (%s instanceof %s)",
+                Constants.WRAPPER, Constants.WRAPPER, MPJBaseJoin.class.getName()), true);
+    }
 }
diff --git a/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/mp/SelectMapsPage.java b/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/mp/SelectMapsPage.java
index 41e08a2..b9df82d 100644
--- a/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/mp/SelectMapsPage.java
+++ b/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/mp/SelectMapsPage.java
@@ -45,4 +45,10 @@ public class SelectMapsPage extends com.baomidou.mybatisplus.core.injector.metho
         return SqlScriptUtils.convertChoose(String.format("%s == null or !(%s instanceof %s)", Constants.WRAPPER, Constants.WRAPPER, MPJBaseJoin.class.getName()),
                 selectColumns, mpjSqlSelectColumns() + StringPool.SPACE + selectColumns);
     }
+
+    @Override
+    protected String sqlComment() {
+        return super.sqlComment() + StringPool.NEWLINE + SqlScriptUtils.convertIf("${ew.unionSql}", String.format("%s != null and (%s instanceof %s)",
+                Constants.WRAPPER, Constants.WRAPPER, MPJBaseJoin.class.getName()), true);
+    }
 }
diff --git a/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/mp/SelectObjs.java b/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/mp/SelectObjs.java
index d6543a8..46f12ef 100644
--- a/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/mp/SelectObjs.java
+++ b/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/mp/SelectObjs.java
@@ -39,4 +39,10 @@ public class SelectObjs extends com.baomidou.mybatisplus.core.injector.methods.S
         return SqlScriptUtils.convertChoose(String.format("%s == null or !(%s instanceof %s)", Constants.WRAPPER, Constants.WRAPPER, MPJBaseJoin.class.getName()),
                 selectColumns, mpjSqlSelectColumns() + StringPool.SPACE + selectColumns);
     }
+
+    @Override
+    protected String sqlComment() {
+        return super.sqlComment() + StringPool.NEWLINE + SqlScriptUtils.convertIf("${ew.unionSql}", String.format("%s != null and (%s instanceof %s)",
+                Constants.WRAPPER, Constants.WRAPPER, MPJBaseJoin.class.getName()), true);
+    }
 }
diff --git a/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/mp/SelectOne.java b/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/mp/SelectOne.java
index 4d3f74f..1f93b0e 100644
--- a/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/mp/SelectOne.java
+++ b/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/mp/SelectOne.java
@@ -44,4 +44,10 @@ public class SelectOne extends com.baomidou.mybatisplus.core.injector.methods.Se
         return SqlScriptUtils.convertChoose(String.format("%s == null or !(%s instanceof %s)", Constants.WRAPPER, Constants.WRAPPER, MPJBaseJoin.class.getName()),
                 selectColumns, mpjSqlSelectColumns() + StringPool.SPACE + selectColumns);
     }
+
+    @Override
+    protected String sqlComment() {
+        return super.sqlComment() + StringPool.NEWLINE + SqlScriptUtils.convertIf("${ew.unionSql}", String.format("%s != null and (%s instanceof %s)",
+                Constants.WRAPPER, Constants.WRAPPER, MPJBaseJoin.class.getName()), true);
+    }
 }
diff --git a/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/mp/SelectPage.java b/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/mp/SelectPage.java
index 371cb68..5d20d10 100644
--- a/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/mp/SelectPage.java
+++ b/mybatis-plus-join-core/src/main/java/com/github/yulichang/method/mp/SelectPage.java
@@ -45,4 +45,10 @@ public class SelectPage extends com.baomidou.mybatisplus.core.injector.methods.S
         return SqlScriptUtils.convertChoose(String.format("%s == null or !(%s instanceof %s)", Constants.WRAPPER, Constants.WRAPPER, MPJBaseJoin.class.getName()),
                 selectColumns, mpjSqlSelectColumns() + StringPool.SPACE + selectColumns);
     }
+
+    @Override
+    protected String sqlComment() {
+        return super.sqlComment() + StringPool.NEWLINE + SqlScriptUtils.convertIf("${ew.unionSql}", String.format("%s != null and (%s instanceof %s)",
+                Constants.WRAPPER, Constants.WRAPPER, MPJBaseJoin.class.getName()), true);
+    }
 }
diff --git a/mybatis-plus-join-core/src/main/java/com/github/yulichang/toolkit/WrapperUtils.java b/mybatis-plus-join-core/src/main/java/com/github/yulichang/toolkit/WrapperUtils.java
index 3416ab5..68772e0 100644
--- a/mybatis-plus-join-core/src/main/java/com/github/yulichang/toolkit/WrapperUtils.java
+++ b/mybatis-plus-join-core/src/main/java/com/github/yulichang/toolkit/WrapperUtils.java
@@ -19,7 +19,7 @@ import java.util.Optional;
  */
 public class WrapperUtils {
 
-    public static <T, R> String buildSqlByWrapper(Class<T> clazz, MPJLambdaWrapper<T> wrapper, SFunction<R, ?> alias) {
+    public static <T, R> String buildSubSqlByWrapper(Class<T> clazz, MPJLambdaWrapper<T> wrapper, SFunction<R, ?> alias) {
         TableInfo tableInfo = TableHelper.get(clazz);
         Asserts.hasTable(tableInfo, clazz);
         String first = Optional.ofNullable(wrapper.getSqlFirst()).orElse(StringPool.EMPTY);
@@ -40,7 +40,7 @@ public class WrapperUtils {
                 ((wrapper.isEmptyOfNormal() ? StringPool.EMPTY : (hasWhere ? " AND " : " WHERE ")) + wrapper.getSqlSegment()) : StringPool.EMPTY;
 
         String sqlComment = Optional.ofNullable(wrapper.getSqlComment()).orElse(StringPool.EMPTY);
-        return String.format("(%s SELECT %s FROM %s %s %s %s %s %s %s) AS %s",
+        return String.format(" (%s SELECT %s FROM %s %s %s %s %s %s %s) AS %s ",
                 first,
                 wrapper.getSqlSelect(),
                 tableInfo.getTableName(),
@@ -53,6 +53,39 @@ public class WrapperUtils {
                 LambdaUtils.getName(alias));
     }
 
+    public static String buildUnionSqlByWrapper(Class<?> clazz, MPJLambdaWrapper<?> wrapper) {
+        TableInfo tableInfo = TableHelper.get(clazz);
+        Asserts.hasTable(tableInfo, clazz);
+        String first = Optional.ofNullable(wrapper.getSqlFirst()).orElse(StringPool.EMPTY);
+        boolean hasWhere = false;
+        String entityWhere = getEntitySql(tableInfo, wrapper);
+        if (StringUtils.isNotBlank(entityWhere)) {
+            hasWhere = true;
+        }
+        String mainLogic = mainLogic(hasWhere, clazz, wrapper);
+        if (StringUtils.isNotBlank(mainLogic)) {
+            hasWhere = true;
+        }
+        String subLogic = subLogic(hasWhere, wrapper);
+        if (StringUtils.isNotBlank(subLogic)) {
+            hasWhere = true;
+        }
+        String sqlSegment = (wrapper.getSqlSegment() != null && StringUtils.isNotBlank(wrapper.getSqlSegment())) ?
+                ((wrapper.isEmptyOfNormal() ? StringPool.EMPTY : (hasWhere ? " AND " : " WHERE ")) + wrapper.getSqlSegment()) : StringPool.EMPTY;
+
+        String sqlComment = Optional.ofNullable(wrapper.getSqlComment()).orElse(StringPool.EMPTY);
+        return String.format(" %s SELECT %s FROM %s %s %s %s %s %s %s ",
+                first,
+                wrapper.getSqlSelect(),
+                tableInfo.getTableName(),
+                wrapper.getAlias(),
+                wrapper.getFrom(),
+                mainLogic,
+                subLogic,
+                sqlSegment,
+                sqlComment);
+    }
+
     private static <T> String formatParam(MPJLambdaWrapper<T> wrapper, Object param) {
         final String genParamName = Constants.WRAPPER_PARAM + wrapper.getParamNameSeq().incrementAndGet();
         final String paramStr = wrapper.getParamAlias() + ".paramNameValuePairs." + genParamName;
@@ -60,8 +93,8 @@ public class WrapperUtils {
         return SqlScriptUtils.safeParam(paramStr, null);
     }
 
-    private static <T> String getEntitySql(TableInfo tableInfo, MPJLambdaWrapper<T> wrapper) {
-        T obj = wrapper.getEntity();
+    private static String getEntitySql(TableInfo tableInfo, MPJLambdaWrapper<?> wrapper) {
+        Object obj = wrapper.getEntity();
         if (Objects.isNull(obj)) {
             return StringPool.EMPTY;
         }
@@ -90,7 +123,7 @@ public class WrapperUtils {
         return sb.toString();
     }
 
-    private static <T> String mainLogic(boolean hasWhere, Class<T> clazz, MPJLambdaWrapper<T> wrapper) {
+    private static String mainLogic(boolean hasWhere, Class<?> clazz, MPJLambdaWrapper<?> wrapper) {
         String info = LogicInfoUtils.getLogicInfo(null, clazz, true, wrapper.getAlias());
         if (StringUtils.isNotBlank(info)) {
             if (hasWhere) {
@@ -101,7 +134,7 @@ public class WrapperUtils {
         return StringPool.EMPTY;
     }
 
-    private static <T> String subLogic(boolean hasWhere, MPJLambdaWrapper<T> wrapper) {
+    private static String subLogic(boolean hasWhere, MPJLambdaWrapper<?> wrapper) {
         String sql = wrapper.getSubLogicSql();
         if (StringUtils.isNotBlank(sql)) {
             if (hasWhere) {
diff --git a/mybatis-plus-join-core/src/main/java/com/github/yulichang/wrapper/MPJLambdaWrapper.java b/mybatis-plus-join-core/src/main/java/com/github/yulichang/wrapper/MPJLambdaWrapper.java
index df6cc9d..925d409 100644
--- a/mybatis-plus-join-core/src/main/java/com/github/yulichang/wrapper/MPJLambdaWrapper.java
+++ b/mybatis-plus-join-core/src/main/java/com/github/yulichang/wrapper/MPJLambdaWrapper.java
@@ -2,10 +2,7 @@ package com.github.yulichang.wrapper;
 
 import com.baomidou.mybatisplus.core.conditions.SharedString;
 import com.baomidou.mybatisplus.core.conditions.segments.MergeSegments;
-import com.baomidou.mybatisplus.core.toolkit.ArrayUtils;
-import com.baomidou.mybatisplus.core.toolkit.CollectionUtils;
-import com.baomidou.mybatisplus.core.toolkit.StringPool;
-import com.baomidou.mybatisplus.core.toolkit.StringUtils;
+import com.baomidou.mybatisplus.core.toolkit.*;
 import com.baomidou.mybatisplus.core.toolkit.support.SFunction;
 import com.github.yulichang.toolkit.Constant;
 import com.github.yulichang.toolkit.LambdaUtils;
@@ -56,6 +53,11 @@ public class MPJLambdaWrapper<T> extends MPJAbstractLambdaWrapper<T, MPJLambdaWr
     @Getter
     private final List<Label<?>> resultMapMybatisLabel = new ArrayList<>();
 
+    /**
+     * union sql
+     */
+    private SharedString unionSql;
+
 
     /**
      * 推荐使用 带 class 的构造方法
@@ -190,11 +192,49 @@ public class MPJLambdaWrapper<T> extends MPJAbstractLambdaWrapper<T, MPJLambdaWr
         wrapper.alias = st;
         wrapper.subTableAlias = st;
         consumer.accept(wrapper);
-        String sql = WrapperUtils.buildSqlByWrapper(clazz, wrapper, alias);
+        String sql = WrapperUtils.buildSubSqlByWrapper(clazz, wrapper, alias);
         this.selectColumns.add(new SelectString(sql, hasAlias, this.alias));
         return typedThis;
     }
 
+    /**
+     * union
+     */
+    @SuppressWarnings("UnusedReturnValue")
+    public final MPJLambdaWrapper<T> union(MPJLambdaWrapper<?>... wrappers) {
+        StringBuilder sb = new StringBuilder();
+        for (MPJLambdaWrapper<?> wrapper : wrappers) {
+            Class<?> entityClass = wrapper.getEntityClass();
+            Assert.notNull(entityClass, "请使用 new MPJLambdaWrapper(主表.class) 或 JoinWrappers.lambda(主表.class) 构造方法");
+            sb.append(" UNION ")
+                    .append(WrapperUtils.buildUnionSqlByWrapper(entityClass, wrapper));
+        }
+        if (Objects.isNull(unionSql)) {
+            unionSql = SharedString.emptyString();
+        }
+        unionSql.setStringValue(unionSql.getStringValue() + sb);
+        return typedThis;
+    }
+
+    /**
+     * union all
+     */
+    @SafeVarargs
+    public final <E, F> MPJLambdaWrapper<T> unionAll(MPJLambdaWrapper<T>... wrappers) {
+        StringBuilder sb = new StringBuilder();
+        for (MPJLambdaWrapper<?> wrapper : wrappers) {
+            Class<?> entityClass = wrapper.getEntityClass();
+            Assert.notNull(entityClass, "请使用 new MPJLambdaWrapper(主表.class) 或 JoinWrappers.lambda(主表.class) 构造方法");
+            sb.append(" UNION ALL ")
+                    .append(WrapperUtils.buildUnionSqlByWrapper(entityClass, wrapper));
+        }
+        if (Objects.isNull(unionSql)) {
+            unionSql = SharedString.emptyString();
+        }
+        unionSql.setStringValue(unionSql.getStringValue() + sb);
+        return typedThis;
+    }
+
     /**
      * 查询条件 SQL 片段
      */
@@ -242,6 +282,10 @@ public class MPJLambdaWrapper<T> extends MPJAbstractLambdaWrapper<T, MPJLambdaWr
         return sqlSelect.getStringValue();
     }
 
+    @Override
+    public String getUnionSql() {
+        return Optional.ofNullable(unionSql).map(SharedString::getStringValue).orElse(StringPool.EMPTY);
+    }
 
     public boolean getSelectDistinct() {
         return selectDistinct;
diff --git a/mybatis-plus-join-test/test-join/src/test/java/com/github/yulichang/test/join/LambdaWrapperTest.java b/mybatis-plus-join-test/test-join/src/test/java/com/github/yulichang/test/join/LambdaWrapperTest.java
index 1d24c78..52ff454 100644
--- a/mybatis-plus-join-test/test-join/src/test/java/com/github/yulichang/test/join/LambdaWrapperTest.java
+++ b/mybatis-plus-join-test/test-join/src/test/java/com/github/yulichang/test/join/LambdaWrapperTest.java
@@ -1020,10 +1020,28 @@ class LambdaWrapperTest {
         ThreadLocalUtils.set("SELECT ( SELECT st.id FROM `user` st WHERE st.del=false AND (st.id <= ?) limit 1 ) AS pid FROM `user` t LEFT JOIN address t1 ON (t1.user_id = t.id) WHERE t.del=false AND t1.del=false AND (t.id <= ?)");
         MPJLambdaWrapper<UserDO> wrapper = JoinWrappers.lambda(UserDO.class)
                 .selectSub(UserDO.class, w -> w.select(UserDO::getId)
-                        .le(UserDO::getId,1000)
+                        .le(UserDO::getId, 1000)
                         .last("limit 1"), UserDO::getPid)
-                .leftJoin(AddressDO.class,AddressDO::getUserId,UserDO::getId)
-                .le(UserDO::getId,100);
+                .leftJoin(AddressDO.class, AddressDO::getUserId, UserDO::getId)
+                .le(UserDO::getId, 100);
+        wrapper.list();
+        System.out.println(1);
+    }
+
+
+    /**
+     * select 子查询
+     */
+    @Test
+    void union() {
+        MPJLambdaWrapper<UserDO> wrapper = JoinWrappers.lambda(UserDO.class)
+                .selectAll(UserDO.class);
+        MPJLambdaWrapper<UserDO> wrapper1 = JoinWrappers.lambda(UserDO.class)
+                .selectAll(UserDO.class);
+        MPJLambdaWrapper<UserDO> wrapper2 = JoinWrappers.lambda(UserDO.class)
+                .selectAll(UserDO.class);
+
+        wrapper.union(wrapper1, wrapper2);
         wrapper.list();
         System.out.println(1);
     }