[Bug] group_concat support distinct

docs/en/sql-manual/sql-functions/aggregate-functions/group_concat.md

@@ -28,7 +28,7 @@ under the License.
 ### description
 #### Syntax
 
-`VARCHAR GROUP_CONCAT(VARCHAR str[, VARCHAR sep])`
+`VARCHAR GROUP_CONCAT([DISTINCT] VARCHAR str[, VARCHAR sep])`
 
 
 This function is an aggregation function similar to sum (), and group_concat links multiple rows of results in the result set to a string. The second parameter, sep, is a connection symbol between strings, which can be omitted. This function usually needs to be used with group by statements.
@@ -43,22 +43,30 @@ mysql> select value from test;
 | a     |
 | b     |
 | c     |
+| c     |
 +-------+
 
 mysql> select GROUP_CONCAT(value) from test;
 +-----------------------+
 | GROUP_CONCAT(`value`) |
 +-----------------------+
-| a, b, c               |
+| a, b, c, c              |
 +-----------------------+
 
 mysql> select GROUP_CONCAT(value, " ") from test;
 +----------------------------+
 | GROUP_CONCAT(`value`, ' ') |
 +----------------------------+
-| a b c                      |
+| a b c c                     |
 +----------------------------+
 
+mysql> select GROUP_CONCAT(DISTINCT value) from test;
++-----------------------+
+| GROUP_CONCAT(`value`) |
++-----------------------+
+| a, b, c               |
++-----------------------+
+
 mysql> select GROUP_CONCAT(value, NULL) from test;
 +----------------------------+
 | GROUP_CONCAT(`value`, NULL)|

docs/zh-CN/sql-manual/sql-functions/aggregate-functions/group_concat.md

@@ -28,7 +28,7 @@ under the License.
 ### description
 #### Syntax
 
-`VARCHAR GROUP_CONCAT(VARCHAR str[, VARCHAR sep])`
+`VARCHAR GROUP_CONCAT([DISTINCT] VARCHAR str[, VARCHAR sep])`
 
 
 该函数是类似于 sum() 的聚合函数，group_concat 将结果集中的多行结果连接成一个字符串。第二个参数 sep 为字符串之间的连接符号，该参数可以省略。该函数通常需要和 group by 语句一起使用。
@@ -43,20 +43,28 @@ mysql> select value from test;
 | a     |
 | b     |
 | c     |
+| c     |
 +-------+
 
 mysql> select GROUP_CONCAT(value) from test;
 +-----------------------+
 | GROUP_CONCAT(`value`) |
 +-----------------------+
+| a, b, c, c               |
++-----------------------+
+
+mysql> select GROUP_CONCAT(DISTINCT value) from test;
++-----------------------+
+| GROUP_CONCAT(`value`) |
++-----------------------+
 | a, b, c               |
 +-----------------------+
 
 mysql> select GROUP_CONCAT(value, " ") from test;
 +----------------------------+
 | GROUP_CONCAT(`value`, ' ') |
 +----------------------------+
-| a b c                      |
+| a b c c                    |
 +----------------------------+
 
 mysql> select GROUP_CONCAT(value, NULL) from test;

fe/fe-core/src/main/java/org/apache/doris/analysis/FunctionCallExpr.java

@@ -481,10 +481,6 @@ private void analyzeBuiltinAggFunction(Analyzer analyzer) throws AnalysisExcepti
                         "group_concat requires one or two parameters: " + this.toSql());
             }
 
-            if (fnParams.isDistinct()) {
-                throw new AnalysisException("group_concat does not support DISTINCT");
-            }
-
             Expr arg0 = getChild(0);
             if (!arg0.type.isStringType() && !arg0.type.isNull()) {
                 throw new AnalysisException(

fe/fe-core/src/main/java/org/apache/doris/common/util/SqlUtils.java

@@ -17,7 +17,7 @@
 
 package org.apache.doris.common.util;
 
-import org.apache.parquet.Strings;
+import com.google.common.base.Strings;
 
 public class SqlUtils {
     public static String escapeUnquote(String ident) {

fe/fe-core/src/test/java/org/apache/doris/analysis/SelectStmtTest.java

@@ -787,9 +787,12 @@ public void testWithUnionToSql() throws Exception {
     @Test
     public void testSelectOuterJoinSql() throws Exception {
         ConnectContext ctx = UtFrameUtils.createDefaultCtx();
-        String sql1 = "select l.citycode, group_concat(r.username) from db1.table1 l left join db1.table2 r on l.citycode=r.citycode group by l.citycode";
+        String sql1 = "select l.citycode, group_concat(distinct r.username) from db1.table1 l "
+                + "left join db1.table2 r on l.citycode=r.citycode group by l.citycode";
         SelectStmt stmt1 = (SelectStmt) UtFrameUtils.parseAndAnalyzeStmt(sql1, ctx);
         Assert.assertTrue(stmt1.getAnalyzer().getSlotDesc(new SlotId(2)).getIsNullable());
         Assert.assertTrue(stmt1.getAnalyzer().getSlotDescriptor("r.username").getIsNullable());
+        FunctionCallExpr expr = (FunctionCallExpr) stmt1.getSelectList().getItems().get(1).getExpr();
+        Assert.assertTrue(expr.getFnParams().isDistinct());
     }
 }

regression-test/data/query/group_concat/test_group_concat.out

@@ -0,0 +1,7 @@
+-- This file is automatically generated. You should know what you did if you want to edit this
+-- !select --
+false, false
+
+-- !select --
+false
+

regression-test/suites/query/group_concat/test_group_concat.groovy

@@ -0,0 +1,26 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+suite("test_group_concat", "query") {
+    qt_select """
+                SELECT group_concat(k6) FROM test_query_db.test where k6='false'
+              """
+
+    qt_select """
+                SELECT group_concat(DISTINCT k6) FROM test_query_db.test where k6='false'
+              """
+}