songyunlu

SELECT * FROM opp WHERE phone = '1234567' or cellPhone = '7654321';
/* 改寫為 */
SELECT * FROM opp WHERE phone = '1234567' 
UNION 
SELECT * FROM opp WHERE cellPhone = '7654321';

songyunlu

SELECT * FROM opp WHERE phone = '1234567'or phone = '7654321';
/* 改寫為 */
SELECT * FROM opp WHERE phone IN('1234567', '7654321');

songyunlu

/* 欄位定義：`remark` varchar(50) NOT NULL */

/* 執行時間：0.14 秒 */
SELECT `id`, `gift_code` FROM gift WHERE `deal_id` = 640 AND remark = 115127;

/* 執行時間：0.005 秒 */
SELECT `id`, `gift_code` FROM gift WHERE `deal_id` = 640 AND remark = '15127';

songyunlu

/* 執行時間：2.19 秒 */
SELECT phone, COUNT(*) from post GROUP BY phone LIMIT 1;

/* 執行時間：2.02秒 */
SELECT phone, COUNT(*) from post GROUP BY phone ORDER BY NULL LIMIT 1;

songyunlu

SELECT * FROM table WHERE id >= 23423 LIMIT 11;
/* 10 + 1 每頁十筆資料 */
SELECT * FROM table WHERE id >= 23433 LIMIT 11;

songyunlu

UPDATE post SET tag = 1 WHERE id IN (1,2,3);
sleep 0.01;
UPDATE post SET tag = 1 WHERE id IN (4,5,6);
sleep 0.01;
......

songyunlu

SELECT * FROM table1 WHERE id IN (SELECT id FROM table2);

/* 可能引起同步的延遲，還可能導致同步出錯，特別是有設定 AUTO_INCREMENT 時 */
INSERT INTO table1 (SELECT * FROM table2);

songyunlu

package servletutils;

import com.google.common.base.Preconditions;
import javax.servlet.*;
import javax.servlet.http.*;

public class UnhandledExceptionFilter implements Filter {
  
  public interface ErrorHandler {
    void handle(HttpServletRequest request, HttpServletResponse response, Throwable throwable);  

songyunlu

package demo;

import java.util.Arrays;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;

import org.apache.catalina.LifecycleListener;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

songyunlu

public class CassandraEnvironmentRepository implements EnvironmentRepository {

    private static final Logger logger = Logger.getLogger(CassandraEnvironmentRepository.class);

    @Autowired
    private PropertiesRepository propertiesRepository;

    @Override
    public Environment findOne(final String application, final String profile, final String label) {
        Environment result = new Environment(profile, label);