Fix query ok for drop view

sql/plan/drop_view.go

@@ -17,9 +17,9 @@ package plan
 import (
 	errors "gopkg.in/src-d/go-errors.v1"
 
-	"github.com/dolthub/go-mysql-server/sql/mysql_db"
-
 	"github.com/dolthub/go-mysql-server/sql"
+	"github.com/dolthub/go-mysql-server/sql/mysql_db"
+	"github.com/dolthub/go-mysql-server/sql/types"
 )
 
 var ErrDropViewChild = errors.NewKind("any child of DropView must be of type SingleDropView")
@@ -56,8 +56,8 @@ func (dv *SingleDropView) IsReadOnly() bool {
 	return false
 }
 
-// Schema implements the Node interface. It always returns nil.
-func (dv *SingleDropView) Schema() sql.Schema { return nil }
+// Schema implements the Node interface. It always returns Query OK result.
+func (dv *SingleDropView) Schema() sql.Schema { return types.OkResultSchema }
 
 // String implements the fmt.Stringer interface, using sql.TreePrinter to
 // generate the string.
@@ -133,8 +133,8 @@ func (dvs *DropView) Resolved() bool {
 	return true
 }
 
-// Schema implements the Node interface. It always returns nil.
-func (dvs *DropView) Schema() sql.Schema { return nil }
+// Schema implements the Node interface. It always returns Query OK result.
+func (dvs *DropView) Schema() sql.Schema { return types.OkResultSchema }
 
 // String implements the fmt.Stringer interface, using sql.TreePrinter to
 // generate the string.

sql/rowexec/ddl.go

@@ -558,7 +558,7 @@ func (b *BaseBuilder) buildDropView(ctx *sql.Context, n *plan.DropView, row sql.
 		}
 	}
 
-	return sql.RowsToRowIter(), nil
+	return rowIterWithOkResultWithZeroRowsAffected(), nil
 }
 
 func (b *BaseBuilder) buildAlterUser(ctx *sql.Context, a *plan.AlterUser, _ sql.Row) (sql.RowIter, error) {

sql/rowexec/drop_view_test.go

@@ -15,6 +15,7 @@
 package rowexec
 
 import (
+	"io"
 	"testing"
 
 	"github.com/stretchr/testify/require"
@@ -148,3 +149,34 @@ func TestDropNonExistingViewNative(t *testing.T) {
 	require.Error(t, err)
 	require.True(t, sql.ErrViewDoesNotExist.Is(err))
 }
+
+// Tests that DROP VIEW returns an OkResult (not empty set)
+func TestDropViewReturnsOkResult(t *testing.T) {
+	db := memory.NewDatabase("mydb")
+	ctx, view := setupView(t, db)
+
+	singleDropView := plan.NewSingleDropView(db, view.Name())
+	dropView := plan.NewDropView([]sql.Node{singleDropView}, false)
+
+	iter, err := DefaultBuilder.Build(ctx, dropView, nil)
+	require.NoError(t, err)
+
+	// Verify we can read the result and it contains an OkResult with 0 rows affected
+	row, err := iter.Next(ctx)
+	if err != nil {
+		t.Logf("iter.Next returned error: %v", err)
+	}
+	require.NoError(t, err, "Expected to get a row with OkResult, but got error: %v", err)
+	require.NotNil(t, row)
+	require.Equal(t, 1, len(row), "Expected 1 column in result, got %d", len(row))
+
+	okResult, ok := row[0].(types.OkResult)
+	require.True(t, ok, "Expected OkResult, got %T: %v", row[0], row[0])
+	require.Equal(t, uint64(0), okResult.RowsAffected)
+
+	// Verify no more rows (iterator should return io.EOF)
+	_, err = iter.Next(ctx)
+	require.Equal(t, io.EOF, err)
+
+	require.NoError(t, iter.Close(ctx))
+}