stdlib sql return precision for DateTime64

clickhouse_std.go

@@ -445,10 +445,16 @@ func (r *stdRows) ColumnTypePrecisionScale(idx int) (precision, scale int64, ok
 	switch col := r.rows.block.Columns[idx].(type) {
 	case *column.Decimal:
 		return col.Precision(), col.Scale(), true
+	case *column.DateTime64:
+		p, ok := col.Precision()
+		return p, 0, ok
 	case interface{ Base() column.Interface }:
 		switch col := col.Base().(type) {
 		case *column.Decimal:
 			return col.Precision(), col.Scale(), true
+		case *column.DateTime64:
+			p, ok := col.Precision()
+			return p, 0, ok
 		}
 	}
 	return 0, 0, false

lib/column/datetime64.go

@@ -96,6 +96,10 @@ func (col *DateTime64) ScanType() reflect.Type {
 	return scanTypeTime
 }
 
+func (col *DateTime64) Precision() (int64, bool) {
+	return int64(col.col.Precision), col.col.PrecisionSet
+}
+
 func (col *DateTime64) Rows() int {
 	return col.col.Rows()
 }

tests/std/datetime64_test.go

@@ -118,5 +118,26 @@ func TestStdDateTime64(t *testing.T) {
 			require.Equal(t, time.Date(1900, 01, 01, 0, 0, 0, 0, time.UTC), col9)
 			require.Equal(t, time.Unix(0, 0).UTC(), col10)
 		})
+
+		t.Run("DateTime64 precision", func(t *testing.T) {
+			conn, err := GetStdDSNConnection(protocol, useSSL, nil)
+			require.NoError(t, err)
+			if !CheckMinServerVersion(conn, 20, 3, 0) {
+				t.Skip(fmt.Errorf("unsupported clickhouse version"))
+				return
+			}
+
+			rows, err := conn.Query("SELECT toDateTime64(1546300800.123, 3)")
+			require.NoError(t, err)
+
+			columnTypes, err := rows.ColumnTypes()
+			require.NoError(t, err)
+			require.Len(t, columnTypes, 1)
+
+			precision, scale, ok := columnTypes[0].DecimalSize()
+			require.Equal(t, int64(3), precision)
+			require.Equal(t, int64(0), scale)
+			require.True(t, ok)
+		})
 	}
 }