SQLite query watcher

main.c

/* 
	Build
	gcc.exe -Wall -O2  -c main.c -o obj\main.o
	gcc.exe -Wall -O2  -c sqlite3.c -o obj\sqlite3.o
	gcc.exe -o watcher.exe obj\main.o obj\sqlite3.o  -s 
	
	Usage example
	watcher -d "D:/my.sqlite" -q "select * from t order by 1 desc limit 10" - t 2
*/
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include "sqlite3.h"

int main(int argc, char *argv[]) {
	int opt;
	char* query = 0, *dbpath = 0;
	int timer = 5;

	while ((opt = getopt(argc, argv, "t:q:d:")) != -1) {
		switch (opt) {
			case 'q': query = optarg; break;
			case 'd': dbpath = optarg; break;
			case 't': timer = atoi(optarg); break;
		}
	}

	if (!dbpath || !strlen(dbpath) || !query || !strlen(query)) {
		fprintf(stderr,
				"Usage: %s -d dbpath -q query -t timer\n" \
				"Example: %s -d \"D:/my.db\" -q \"select * from t order by 1 desc limit 10\" -t 1\n" \
				"By default timer is 5 sec\n", argv[0], argv[0]);
		exit(EXIT_FAILURE);
	}

	sqlite3 *db;
	if (SQLITE_OK != sqlite3_open(dbpath, &db)) {
		printf("Can't open database: %s\n", dbpath);
		exit(EXIT_FAILURE);
	}

	char createSql[strlen(query) + 200];
	sprintf(createSql, "create table temp.dataset as %s", query);

	while (true) {
		sqlite3_exec(db, "begin", 0, 0, 0);
		if (SQLITE_OK != sqlite3_exec(db, createSql, 0, 0, 0)) {
			printf ("Can't fetch data: %s\n", sqlite3_errmsg(db));
			break;
		}
		sqlite3_exec(db, "create table temp.dataset_old as select * from temp.dataset where 1 = 2", 0, 0, 0);

		sqlite3_stmt* stmt;
		if (SQLITE_OK == sqlite3_prepare_v2(db, "select * from temp.dataset except select * from temp.dataset_old", -1, &stmt, 0)) {
			while (SQLITE_ROW == sqlite3_step(stmt)) {
				int colCount = sqlite3_column_count(stmt);
				for (int colNo = 0; colNo < colCount; colNo++) {
					printf((const char*)sqlite3_column_text(stmt, colNo));
					printf(colNo != colCount - 1 ? "  |  " : "\n");
				}
			}
		}
		sqlite3_finalize(stmt);

		sqlite3_exec(db, "drop table temp.dataset_old", 0, 0, 0);
		sqlite3_exec(db, "alter table temp.dataset rename to dataset_old", 0, 0, 0);
		sqlite3_exec(db, "commit", 0, 0, 0);
		sleep(timer);
	}

	sqlite3_close(db);
}

Windows 32-bit binary - https://sgeproject.narod.ru/watcher.zip