test: add demo for tq

TS-1464

examples/c/tqdemo.c

+/*
+ * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
+ *
+ * This program is free software: you can use, redistribute, and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3
+ * or later ("AGPL"), as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+// TAOS standard API example. The same syntax as MySQL, but only a subset
+// to compile: gcc -o tqdemo tqdemo.c -ltaos
+
+#include <inttypes.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <taos.h>  // TAOS header file
+
+void print_results(TAOS *taos, char *qstr);
+
+int main(int argc, char *argv[]) {
+  char qstr[1024];
+  TAOS_RES *pSql = NULL;
+
+  // connect to server
+  if (argc < 2) {
+    printf("please input server-ip \n");
+    return 0;
+  }
+
+  TAOS *taos = taos_connect(argv[1], "root", "taosdata", NULL, 0);
+  if (taos == NULL) {
+    printf("failed to connect to server, reason:%s\n", "null taos" /*taos_errstr(taos)*/);
+    exit(1);
+  }
+  
+  TAOS_RES* res;
+  // create topic
+  res = taos_query(taos, "create topic tq_test partitions 10");
+  taos_free_result(res);
+
+  res = taos_query(taos, "use tq_test");
+  taos_free_result(res);
+
+  print_results(taos, "show stables");
+  print_results(taos, "show tables");
+
+  // insert data
+  for (int i = 0; i < 10; i++) {
+    char *sql = "insert into p%d values(now + %ds, %d, 'test')";
+    sprintf(qstr, sql, i, i, i);
+    res = taos_query(taos, qstr);
+    taos_free_result(res);
+  }
+
+  // query data
+  print_results(taos, "select * from tq_test.ps");
+
+  taos_close(taos);
+  taos_cleanup();
+}
+
+
+void print_results(TAOS *taos, char *qstr) {
+  TAOS_RES* res;
+  res = taos_query(taos, qstr);
+  if (res == NULL || taos_errno(res) != 0) {
+    printf("failed to select, reason:%s\n", taos_errstr(res));
+    taos_free_result(res);
+    exit(1);
+  }
+
+  TAOS_ROW    row;
+  int         rows = 0;
+  int         num_fields = taos_field_count(res);
+  TAOS_FIELD *fields = taos_fetch_fields(res);
+
+  printf("num_fields = %d\n", num_fields);
+  printf("%s result:\n", qstr);
+  // fetch the records row by row
+  while ((row = taos_fetch_row(res))) {
+    char temp[1024] = {0};
+    rows++;
+    taos_print_row(temp, row, fields, num_fields);
+    printf("%s\n", temp);
+  }
+  taos_free_result(res);
+}