Выборка с максимальным значением поля по группировке
dump
задача - найти первые статусы по звонку (id_call)
-- -- Current Database: `localdb` -- CREATE DATABASE /*!32312 IF NOT EXISTS*/ `localdb` /*!40100 DEFAULT CHARACTER SET utf8 */; USE `localdb`; -- MySQL dump 10.13 Distrib 5.6.22, for Win32 (x86) -- -- Host: localhost Database: localdb -- ------------------------------------------------------ -- Server version 5.6.26 /*!40101 SET @OLD_CHARACTER_SET_CLIENT=@@CHARACTER_SET_CLIENT */; /*!40101 SET @OLD_CHARACTER_SET_RESULTS=@@CHARACTER_SET_RESULTS */; /*!40101 SET @OLD_COLLATION_CONNECTION=@@COLLATION_CONNECTION */; /*!40101 SET NAMES utf8 */; /*!40103 SET @OLD_TIME_ZONE=@@TIME_ZONE */; /*!40103 SET TIME_ZONE='+00:00' */; /*!40014 SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0 */; /*!40014 SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0 */; /*!40101 SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='NO_AUTO_VALUE_ON_ZERO' */; /*!40111 SET @OLD_SQL_NOTES=@@SQL_NOTES, SQL_NOTES=0 */; -- -- Table structure for table `call_history` -- DROP TABLE IF EXISTS `call_history`; /*!40101 SET @saved_cs_client = @@character_set_client */; /*!40101 SET character_set_client = utf8 */; CREATE TABLE `call_history` ( `id` int(11) NOT NULL AUTO_INCREMENT COMMENT 'PK', `id_call` int(11) NOT NULL COMMENT 'общий ид для всех звонков', `dt_status` datetime(6) NOT NULL DEFAULT CURRENT_TIMESTAMP(6) COMMENT 'дата звонка', `status` varchar(256) DEFAULT NULL COMMENT 'текстовый статус', PRIMARY KEY (`id`), UNIQUE KEY `id` (`id`) ) ENGINE=InnoDB AUTO_INCREMENT=9 DEFAULT CHARSET=utf8 PACK_KEYS=0; /*!40101 SET character_set_client = @saved_cs_client */; -- -- Dumping data for table `call_history` -- LOCK TABLES `call_history` WRITE; /*!40000 ALTER TABLE `call_history` DISABLE KEYS */; INSERT INTO `call_history` VALUES (1,1,'2016-05-19 08:23:29.000000','недозвон'),(2,1,'2016-05-19 08:24:29.000000','ответ'),(3,2,'2016-05-19 08:24:17.000000','недозвон'),(4,2,'2016-05-19 08:23:17.000000','test'),(5,2,'2016-05-19 08:25:17.000000','ответ'),(6,3,'2016-05-19 08:24:48.000000','ответ'),(7,3,'2016-05-19 08:23:48.000000','недозвон'),(8,3,'2016-05-19 08:25:48.000000','test'); /*!40000 ALTER TABLE `call_history` ENABLE KEYS */; UNLOCK TABLES; /*!40103 SET TIME_ZONE=@OLD_TIME_ZONE */; /*!40101 SET SQL_MODE=@OLD_SQL_MODE */; /*!40014 SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS */; /*!40014 SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS */; /*!40101 SET CHARACTER_SET_CLIENT=@OLD_CHARACTER_SET_CLIENT */; /*!40101 SET CHARACTER_SET_RESULTS=@OLD_CHARACTER_SET_RESULTS */; /*!40101 SET COLLATION_CONNECTION=@OLD_COLLATION_CONNECTION */; /*!40111 SET SQL_NOTES=@OLD_SQL_NOTES */; -- Dump completed on 2016-05-19 8:54:08
задача - найти первые статусы по звонку (id_call)
SELECT min(dt_status), status FROM call_history GROUP BY id_call
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