diff --git a/src/pl/tcl/pltcl.c b/src/pl/tcl/pltcl.c
new file mode 100644
index 185d5be..499a9ea
--- a/src/pl/tcl/pltcl.c
+++ b/src/pl/tcl/pltcl.c
@@ -2441,6 +2441,7 @@ pltcl_process_SPI_result(Tcl_Interp *int
 		case SPI_OK_INSERT:
 		case SPI_OK_DELETE:
 		case SPI_OK_UPDATE:
+		case SPI_OK_MERGE:
 			Tcl_SetObjResult(interp, Tcl_NewWideIntObj(ntuples));
 			break;