cleanup
diff --git a/Makefile b/Makefile
index 5bfddba..f73b17c 100644
--- a/Makefile
+++ b/Makefile
@@ -6,6 +6,8 @@
 SQL_INSTALL = sql/$(EXTENSION)--$(EXTVERSION).sql
 DATA = $(SQL_INSTALL)
 
+EXTRA_CLEAN = $(SQL_INSTALL)
+
 OBJS = src/base64.o src/common.o \
   src/kll_float_sketch_pg_functions.o src/kll_float_sketch_c_adapter.o \
   src/cpc_sketch_pg_functions.o src/cpc_sketch_c_adapter.o \