diff --git a/docs/examples/c/create_db_demo.c b/docs/examples/c/create_db_demo.c
index 7ae41da65c..7b9191ec16 100644
--- a/docs/examples/c/create_db_demo.c
+++ b/docs/examples/c/create_db_demo.c
@@ -39,8 +39,19 @@ static int DemoCreateDB() {
     return -1;
   }
 
+  // drop database if exists
+  TAOS_RES *result = taos_query(taos, "DROP DATABASE IF EXISTS power");
+  code = taos_errno(result);
+  if (code != 0) {
+    fprintf(stderr, "Failed to drop database power, ErrCode: 0x%x, ErrMessage: %s.\n", code, taos_errstr(result));
+    taos_close(taos);
+    taos_cleanup();
+    return -1;
+  }
+  taos_free_result(result);
+
   // create database
-  TAOS_RES *result = taos_query(taos, "CREATE DATABASE IF NOT EXISTS power");
+  result = taos_query(taos, "CREATE DATABASE IF NOT EXISTS power");
   code = taos_errno(result);
   if (code != 0) {
     fprintf(stderr, "Failed to create database power, ErrCode: 0x%x, ErrMessage: %s.\n", code, taos_errstr(result));
diff --git a/docs/examples/c/sml_insert_demo.c b/docs/examples/c/sml_insert_demo.c
index 63870d90b6..ba9f47be67 100644
--- a/docs/examples/c/sml_insert_demo.c
+++ b/docs/examples/c/sml_insert_demo.c
@@ -38,8 +38,19 @@ static int DemoSmlInsert() {
     return -1;
   }
 
+  // drop database if exists
+  TAOS_RES *result = taos_query(taos, "DROP DATABASE IF EXISTS power");
+  code = taos_errno(result);
+  if (code != 0) {
+    fprintf(stderr, "Failed to drop database power, ErrCode: 0x%x, ErrMessage: %s.\n", code, taos_errstr(result));
+    taos_close(taos);
+    taos_cleanup();
+    return -1;
+  }
+  taos_free_result(result);
+
   // create database
-  TAOS_RES *result = taos_query(taos, "CREATE DATABASE IF NOT EXISTS power");
+  result = taos_query(taos, "CREATE DATABASE IF NOT EXISTS power");
   code = taos_errno(result);
   if (code != 0) {
     fprintf(stderr, "Failed to create database power, ErrCode: 0x%x, ErrMessage: %s.\n", code, taos_errstr(result));
diff --git a/tests/docs-examples-test/c.sh b/tests/docs-examples-test/c.sh
index d3e30b081d..0713cc53e0 100644
--- a/tests/docs-examples-test/c.sh
+++ b/tests/docs-examples-test/c.sh
@@ -14,15 +14,15 @@ LOG_FILE="docs-c-test-out.log"
 
 > $LOG_FILE
 
-TEST_EXES=(
+declare -a TEST_EXES=(
     "docs_connect_example"
     "docs_create_db_demo"
     "docs_insert_data_demo"
     "docs_query_data_demo"
     "docs_with_reqid_demo"
-    "docs_sml_insert_demo"
     "docs_stmt_insert_demo"
     "docs_tmq_demo"
+    "docs_sml_insert_demo"
 )
 
 totalCases=0