diff --git a/tests/examples/c/apitest.c b/tests/examples/c/apitest.c
index b2411d1212de3cb930ce6d7032e6b1f8ec0dcc5d..2961750efce3f1e746aa2e82ecb5160488065681 100644
--- a/tests/examples/c/apitest.c
+++ b/tests/examples/c/apitest.c
@@ -402,10 +402,6 @@ void verify_prepare(TAOS* taos) {
   taos_stmt_close(stmt);
 }
 
-
-
-
-
 void verify_prepare2(TAOS* taos) {
   TAOS_RES* result = taos_query(taos, "drop database if exists test;");
   taos_free_result(result);
@@ -531,10 +527,9 @@ void verify_prepare2(TAOS* taos) {
   params[9].is_null = is_null;
   params[9].num = 10;
 
-
-  sql = "insert into ? values(?,?,?,?,?,?,?,?,?,?)";
+  sql = "insert into ? (ts, b, v1, v2, v4, v8, f4, f8, bin, blob) values(?,?,?,?,?,?,?,?,?,?)";
   code = taos_stmt_prepare(stmt, sql, 0);
-  if (code != 0){
+  if (code != 0) {
     printf("\033[31mfailed to execute taos_stmt_prepare. code:0x%x\033[0m\n", code);
   }
 
@@ -577,9 +572,8 @@ void verify_prepare2(TAOS* taos) {
     printf("\033[31mfailed to execute insert statement.\033[0m\n");
     return;
   }
-  taos_stmt_close(stmt);
-
 
+  taos_stmt_close(stmt);
 
   // query the records
   stmt = taos_stmt_init(taos);
@@ -623,9 +617,16 @@ void verify_prepare2(TAOS* taos) {
 
   taos_free_result(result);
   taos_stmt_close(stmt);
-}
-
 
+  free(t8_len);
+  free(t16_len);
+  free(t32_len);
+  free(t64_len);
+  free(float_len);
+  free(double_len);
+  free(bin_len);
+  free(blob_len);
+}
 
 void verify_prepare3(TAOS* taos) {
   TAOS_RES* result = taos_query(taos, "drop database if exists test;");
@@ -810,7 +811,6 @@ void verify_prepare3(TAOS* taos) {
     blob_len[i] = (int32_t)strlen(v.blob[i]);
   }
 
-
   taos_stmt_bind_param_batch(stmt, params);
   taos_stmt_add_batch(stmt);
   
@@ -852,10 +852,12 @@ void verify_prepare3(TAOS* taos) {
   int         rows = 0;
   int         num_fields = taos_num_fields(result);
   TAOS_FIELD *fields = taos_fetch_fields(result);
-  char        temp[256];
+  char        temp[256] = {0};
 
   // fetch the records row by row
   while ((row = taos_fetch_row(result))) {
+    memset(temp, 0, sizeof(temp)/sizeof(temp[0]));
+
     rows++;
     taos_print_row(temp, row, fields, num_fields);
     printf("%s\n", temp);
@@ -863,9 +865,16 @@ void verify_prepare3(TAOS* taos) {
 
   taos_free_result(result);
   taos_stmt_close(stmt);
-}
-
 
+  free(t8_len);
+  free(t16_len);
+  free(t32_len);
+  free(t64_len);
+  free(float_len);
+  free(double_len);
+  free(bin_len);
+  free(blob_len);
+}
 
 void retrieve_callback(void *param, TAOS_RES *tres, int numOfRows)
 {