Merge pull request h2database#165 from Myp/master

Fix compatibility postgresql function string_agg

Author: grandinj

h2/src/main/org/h2/command/Parser.java

@@ -2293,8 +2293,9 @@ private Expression readAggregate(int aggregateType, String aggregateName) {
             }
         } else if (aggregateType == Aggregate.GROUP_CONCAT) {
             Aggregate agg = null;
+            boolean distinct = readIf("DISTINCT");
+
             if (equalsToken("GROUP_CONCAT", aggregateName)) {
-                boolean distinct = readIf("DISTINCT");
                 agg = new Aggregate(Aggregate.GROUP_CONCAT,
                     readExpression(), currentSelect, distinct);
                 if (readIf("ORDER")) {
@@ -2308,9 +2309,14 @@ private Expression readAggregate(int aggregateType, String aggregateName) {
             } else if (equalsToken("STRING_AGG", aggregateName)) {
                 // PostgreSQL compatibility: string_agg(expression, delimiter)
                 agg = new Aggregate(Aggregate.GROUP_CONCAT,
-                    readExpression(), currentSelect, false);
+                    readExpression(), currentSelect, distinct);
                 read(",");
                 agg.setGroupConcatSeparator(readExpression());
+
+                if(readIf("ORDER")) {
+                   read("BY");
+                   agg.setGroupConcatOrder(parseSimpleOrderList());
+                }
             }
             r = agg;
         } else {

h2/src/test/org/h2/test/TestAll.java

@@ -148,6 +148,7 @@
 import org.h2.test.synth.TestOuterJoins;
 import org.h2.test.synth.TestRandomCompare;
 import org.h2.test.synth.TestRandomSQL;
+import org.h2.test.synth.TestStringAggCompatibility;
 import org.h2.test.synth.TestTimer;
 import org.h2.test.synth.sql.TestSynth;
 import org.h2.test.synth.thread.TestMulti;
@@ -759,6 +760,7 @@ private void test() throws SQLException {
         addTest(new TestMultiThreaded());
         addTest(new TestOuterJoins());
         addTest(new TestNestedJoins());
+        addTest(new TestStringAggCompatibility());
 
         runAddedTests();
 

h2/src/test/org/h2/test/synth/TestStringAggCompatibility.java

@@ -0,0 +1,78 @@
+package org.h2.test.synth;
+
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+
+import org.h2.test.TestBase;
+
+/**
+ * Test for check compatibility with posgresql function string_agg()
+ *
+ * */
+public class TestStringAggCompatibility extends TestBase {
+
+    public static final String STRING_AGG_DB = "stringAgg";
+
+    private Connection conn;
+
+    public static void main(String[] args) throws Exception {
+        TestBase.createCaller().init().test();
+    }
+
+    @Override
+    public void test() throws Exception {
+        deleteDb(STRING_AGG_DB);
+
+        conn = getConnection(STRING_AGG_DB);
+
+        prepareDb();
+
+
+
+
+
+        testWhenOrderByMissing();
+        testWithOrderBy();
+    }
+
+    private void testWithOrderBy() throws SQLException {
+        ResultSet result = query("select string_agg(b, ', ' order by b desc) from stringAgg group by a; ");
+
+        assertTrue(result.next());
+        assertEquals("3, 2, 1", result.getString(1));
+    }
+
+    private void testWhenOrderByMissing() throws SQLException {
+        ResultSet result = query("select string_agg(b, ', ') from stringAgg group by a; ");
+
+        assertTrue(result.next());
+        assertEquals("1, 2, 3", result.getString(1));
+    }
+
+
+    private ResultSet query(String q) throws SQLException {
+        PreparedStatement st = conn.prepareStatement(q);
+
+        st.execute();
+
+        return st.getResultSet();
+    }
+
+    private void prepareDb() throws SQLException {
+        exec("create table stringAgg(\n" +
+                " a int not null,\n" +
+                " b varchar(50) not null\n" +
+                ");");
+
+           exec("insert into stringAgg values(1, '1')");
+           exec("insert into stringAgg values(1, '2')");
+           exec("insert into stringAgg values(1, '3')");
+
+    }
+
+    private void exec(String sql) throws SQLException {
+        conn.prepareStatement(sql).execute();
+    }
+}