Fix column type for DATE_TRUNC

h2/src/main/org/h2/expression/Function.java

@@ -2197,6 +2197,18 @@ public class Function extends Expression implements FunctionCall {
         long p;
         Expression p0 = args.length < 1 ? null : args[0];
         switch (info.type) {
+        case DATE_TRUNC: {
+            Expression p1 = args[1];
+            t = p1.getType();
+            if (t == Value.TIMESTAMP_TZ) {
+                p = d = ValueTimestampTimeZone.DEFAULT_PRECISION;
+            } else {
+                t = Value.TIMESTAMP;
+                p = d = ValueTimestamp.DEFAULT_PRECISION;
+            }
+            s = ValueTimestamp.MAXIMUM_SCALE;
+            break;
+        }
         case IFNULL:
         case NULLIF:
         case COALESCE:

h2/src/test/org/h2/test/db/TestFunctions.java

@@ -113,6 +113,7 @@ public class TestFunctions extends TestDb implements AggregateFunction {
         testNvl2();
         testConcatWs();
         testTruncate();
+        testDateTrunc();
         testToCharFromDateTime();
         testToCharFromNumber();
         testToCharFromText();
@@ -1239,6 +1240,23 @@ public class TestFunctions extends TestDb implements AggregateFunction {
         conn.close();
     }
 
+    private void testDateTrunc() throws SQLException {
+        deleteDb("functions");
+        Connection conn = getConnection("functions");
+        Statement stat = conn.createStatement();
+        stat.execute("CREATE TABLE TEST(S VARCHAR, TS TIMESTAMP, D DATE, T TIME, TZ TIMESTAMP WITH TIME ZONE)");
+        stat.execute("INSERT INTO TEST VALUES ('2010-01-01 10:11:12', '2010-01-01 10:11:12', '2010-01-01', '10:11:12', '2010-01-01 10:11:12Z')");
+        ResultSetMetaData md = stat.executeQuery("SELECT DATE_TRUNC('HOUR', S), DATE_TRUNC('HOUR', TS),"
+                + " DATE_TRUNC('HOUR', D), DATE_TRUNC('HOUR', T), DATE_TRUNC('HOUR', TZ) FROM TEST")
+                .getMetaData();
+        assertEquals(Types.TIMESTAMP, md.getColumnType(1));
+        assertEquals(Types.TIMESTAMP, md.getColumnType(2));
+        assertEquals(Types.TIMESTAMP, md.getColumnType(3));
+        assertEquals(Types.TIMESTAMP, md.getColumnType(4));
+        assertEquals(Types.TIMESTAMP_WITH_TIMEZONE, md.getColumnType(5));
+        conn.close();
+    }
+
     private void testTranslate() throws SQLException {
         Connection conn = getConnection("functions");
         Statement stat = conn.createStatement();