如何通過最近的日期在3臺SQL查詢

篩選我有一所學校，其中每個場（pj001_courses），有一個或多個相關經驗（任務）的MySQL數據庫。中間有一個連接表（pj001_courses_tasks_c）。如何通過最近的日期在3臺SQL查詢

pj001_courses：（ID，姓名）

pj001_courses_tasks_c：（ID，pj001_courses_taskspj001_courses_ida，pj001_courses_taskstasks_idb）

任務：（ID，姓名，DATE_START，DATE_MODIFIED，狀態）

WHERE：pj001_courses.id = pj001_courses_tasks_c.pj001_courses_taskspj001_courses_ida AND tasks.id = pj001_courses_tasks_c。 pj001_courses_taskstasks_idb

我試圖獲得與我的查詢，是所有與（「完成」狀態=）最近的「已完成」課課程列表，將包括以下字段：

Corso大街，標識Corso大街， idlez， Lezione， DATE_START， DATE_MODIFIED

下面在這裏，你可以找到的代碼來創建示例MySQL測試數據庫：

-- phpMyAdmin SQL Dump 
 
-- version 4.0.10deb1 
 
-- http://www.phpmyadmin.net 
 
-- 
 
-- Host: localhost 
 
-- Generato il: Apr 07, 2017 alle 08:24 
 
-- Versione del server: 5.5.53-0ubuntu0.14.04.1 
 
-- Versione PHP: 5.5.9-1ubuntu4.20 
 

 
SET SQL_MODE = "NO_AUTO_VALUE_ON_ZERO"; 
 
SET time_zone = "+00:00"; 
 

 

 
/*!40101 SET @[email protected]@CHARACTER_SET_CLIENT */; 
 
/*!40101 SET @[email protected]@CHARACTER_SET_RESULTS */; 
 
/*!40101 SET @[email protected]@COLLATION_CONNECTION */; 
 
/*!40101 SET NAMES utf8 */; 
 

 
-- 
 
-- Database: `speak_italy_stov` 
 
-- 
 

 
-- -------------------------------------------------------- 
 

 
-- 
 
-- Struttura della tabella `pj001_courses` 
 
-- 
 

 
CREATE TABLE IF NOT EXISTS `pj001_courses` (
 
    `id` char(36) NOT NULL, 
 
    `name` varchar(255) DEFAULT NULL, 
 
    `date_entered` datetime DEFAULT NULL, 
 
    `date_modified` datetime DEFAULT NULL, 
 
    `modified_user_id` char(36) DEFAULT NULL, 
 
    `created_by` char(36) DEFAULT NULL, 
 
    `description` text, 
 
    `deleted` tinyint(1) DEFAULT '0', 
 
    `assigned_user_id` char(36) DEFAULT NULL, 
 
    `startdate` date DEFAULT NULL, 
 
    `startlevel` varchar(5) DEFAULT NULL, 
 
    `time` varchar(5) DEFAULT NULL, 
 
    `lessonsday` text, 
 
    PRIMARY KEY (`id`) 
 
) ENGINE=InnoDB DEFAULT CHARSET=utf8 ROW_FORMAT=COMPACT; 
 

 
-- 
 
-- Dump dei dati per la tabella `pj001_courses` 
 
-- 
 

 
INSERT INTO `pj001_courses` (`id`, `name`, `date_entered`, `date_modified`, `modified_user_id`, `created_by`, `description`, `deleted`, `assigned_user_id`, `startdate`, `startlevel`, `time`, `lessonsday`) VALUES 
 
('3d87bac4-49b0-3acb-3010-56684570afd9', 'Course1', '2015-12-09 15:14:11', '2017-04-06 14:09:28', '1', '1', NULL, 0, '', NULL, NULL, NULL, NULL), 
 
('bb9311ed-8e1b-7715-9222-565f2e684b49', 'Course2', '2015-12-02 17:48:24', '2017-04-06 12:29:58', '1', 'e07880a3-a57d-a20c-9e25-565eb7af093f', NULL, 0, '', '2015-10-14', '80+', '12.45', '^Tuesday^,^Friday^'), 
 
('c608ec6d-960e-eb4f-760d-577b81007df9', 'Course3', '2016-07-05 09:43:30', '2017-04-06 12:31:22', '1', '1', NULL, 0, '', NULL, NULL, NULL, NULL), 
 
('ce7c7bb1-c511-82e5-40bf-56616a7a10cc', 'Course4', '2015-12-04 10:27:39', '2017-04-06 12:35:11', '1', 'c0aa6b17-16d0-baea-c4ae-566162ba3706', NULL, 0, '', '2015-10-05', '10', '10.45', '^Monday^,^Thursday^'), 
 
('eb914486-79d6-07e6-8263-566188671f7a', 'Course5', '2015-12-04 12:33:05', '2016-06-28 13:23:41', '1', 'e07880a3-a57d-a20c-9e25-565eb7af093f', NULL, 0, '', '2015-10-12', 'L.41', '17.00', '^Monday^,^Thursday^'), 
 
('f05b48a8-5a13-5e9f-a823-58e6373e80d7', 'Course6', '2017-04-06 12:41:06', '2017-04-06 12:41:06', '1', '1', NULL, 0, NULL, NULL, '', '', ''); 
 

 
-- -------------------------------------------------------- 
 

 
-- 
 
-- Struttura della tabella `pj001_courses_tasks_c` 
 
-- 
 

 
CREATE TABLE IF NOT EXISTS `pj001_courses_tasks_c` (
 
    `id` varchar(36) NOT NULL, 
 
    `date_modified` datetime DEFAULT NULL, 
 
    `deleted` tinyint(1) DEFAULT '0', 
 
    `pj001_courses_taskspj001_courses_ida` varchar(36) DEFAULT NULL, 
 
    `pj001_courses_taskstasks_idb` varchar(36) DEFAULT NULL, 
 
    PRIMARY KEY (`id`), 
 
    KEY `pj001_courses_tasks_ida1` (`pj001_courses_taskspj001_courses_ida`), 
 
    KEY `pj001_courses_tasks_alt` (`pj001_courses_taskstasks_idb`) 
 
) ENGINE=InnoDB DEFAULT CHARSET=utf8 ROW_FORMAT=COMPACT; 
 

 
-- 
 
-- Dump dei dati per la tabella `pj001_courses_tasks_c` 
 
-- 
 

 
INSERT INTO `pj001_courses_tasks_c` (`id`, `date_modified`, `deleted`, `pj001_courses_taskspj001_courses_ida`, `pj001_courses_taskstasks_idb`) VALUES 
 
('115cbbd6-a061-5ba8-feb4-56756fa6fa6c', '2015-12-19 14:55:56', 0, '3d87bac4-49b0-3acb-3010-56684570afd9', 'fb94089f-57e9-0918-c98f-56756fa424d4'), 
 
('16ed5813-c5d1-f831-9887-56efc618e85a', '2017-04-06 12:18:23', 1, '3d87bac4-49b0-3acb-3010-56684570afd9', '15c65e64-83d5-e27e-9ded-56efc6034ec7'), 
 
('17ef5857-b4a6-6dbf-dedd-58cf9a076172', '2017-03-20 09:03:40', 1, '3d87bac4-49b0-3acb-3010-56684570afd9', '1756da3f-3356-1dea-96b4-58cf9adab8ea'), 
 
('1d05994a-45fa-0370-5304-58cf9b51f8e1', '2017-03-20 09:04:53', 1, '3d87bac4-49b0-3acb-3010-56684570afd9', '1c7f7856-11e6-22a7-786b-58cf9b7d42f4'), 
 
('211b53d7-3bb3-5afe-af27-58cf9ac53d35', '2017-03-20 09:03:40', 1, '3d87bac4-49b0-3acb-3010-56684570afd9', '2092dc4e-ad01-34b8-0b80-58cf9a0b0c90'), 
 
('23e767e6-a6c1-304f-92e3-5671a4ec937d', '2017-04-06 12:38:05', 1, 'eb914486-79d6-07e6-8263-566188671f7a', '226c2475-16a3-e0af-efaa-5671a483f0e2'), 
 
('24c80d60-f81d-c32f-a368-56684568c447', '2015-12-09 15:16:30', 0, 'eb914486-79d6-07e6-8263-566188671f7a', '18f60d90-0554-4880-760b-5668455dd961'), 
 
('27228e24-b7ab-a384-8fe6-58cf9bdbcd56', '2017-03-20 09:04:53', 1, '3d87bac4-49b0-3acb-3010-56684570afd9', '26af672a-823d-2d07-2146-58cf9be2b6f2'), 
 
('284f980c-9dab-2a7f-3526-57738ad682dc', '2017-04-06 12:18:23', 1, '3d87bac4-49b0-3acb-3010-56684570afd9', '2733a707-e734-6a68-c63c-57738a212cd3'), 
 
('2be389fe-1c71-ebde-414e-56616dc0040d', '2015-12-04 10:41:15', 0, 'ce7c7bb1-c511-82e5-40bf-56616a7a10cc', '2996ca74-f2d5-a0bf-0c92-56616d7db8d4'), 
 
('2fdea17a-a236-95b0-586f-58cf9b041a93', '2017-03-20 09:04:53', 1, '3d87bac4-49b0-3acb-3010-56684570afd9', '2f72251d-5ca1-9890-1dc7-58cf9b790e86'), 
 
('30afc042-2d41-ad85-1ace-566b214472a2', '2015-12-11 19:16:20', 0, '3d87bac4-49b0-3acb-3010-56684570afd9', '2f19dd24-1c2f-a245-1856-566b214d7abd'), 
 
('386ce887-a266-8ef6-7d07-58cf9b0b74bb', '2017-03-20 09:04:53', 1, '3d87bac4-49b0-3acb-3010-56684570afd9', '37f7bc74-46c4-0094-f3ad-58cf9b2f00f6'), 
 
('3ac48770-4ed0-fd25-b87f-56616ec579cf', '2015-12-04 10:45:59', 0, 'ce7c7bb1-c511-82e5-40bf-56616a7a10cc', '39109517-1f24-8048-4fca-56616e12fc48'), 
 
('3e440aab-0536-7521-7ac5-5668440a96d9', '2015-12-09 15:13:02', 0, 'bb9311ed-8e1b-7715-9222-565f2e684b49', '16ce0346-064f-c93e-19ca-5668427c30b4'), 
 
('4ab9d6f9-0e63-a8c4-5b7a-58cfd830770a', '2017-04-06 12:18:23', 1, '3d87bac4-49b0-3acb-3010-56684570afd9', '4a1d0654-39fe-1c37-7c0c-58cfd8bd7105'), 
 
('4f02bb09-7576-b8bc-7187-58cf9cee8060', '2017-03-20 09:12:42', 1, '3d87bac4-49b0-3acb-3010-56684570afd9', '4e78ed60-24c8-fcf8-7b62-58cf9ccac2b4'), 
 
('4faff722-1eb8-05ec-2ffe-56718c87b046', '2017-04-06 12:37:27', 1, 'eb914486-79d6-07e6-8263-566188671f7a', '4dd39006-f652-3ae1-d6a6-56718c46617e'), 
 
('59d2498f-8931-7716-3e7b-58e64b5ae4c1', '2017-04-06 14:08:03', 0, '3d87bac4-49b0-3acb-3010-56684570afd9', '595a2e58-76bc-c134-3cef-58e64b59e8d5'), 
 
('5c3f2895-e160-04e9-d79e-58cfd8565416', '2017-03-20 13:26:40', 0, '3d87bac4-49b0-3acb-3010-56684570afd9', '5ba36af1-8f2b-075b-926f-58cfd87a83e7'), 
 
('672b6c68-fcc6-3945-7a47-58cfd8b2d040', '2017-04-06 12:18:23', 1, '3d87bac4-49b0-3acb-3010-56684570afd9', '66a5b45f-4173-387f-8f3d-58cfd8f91b9d'), 
 
('6944176d-6f2b-3369-1e76-5672a363aa43', '2017-04-06 12:38:27', 1, 'eb914486-79d6-07e6-8263-566188671f7a', '6693cd37-0b74-1d97-c395-5672a343260d'), 
 
('6ce06c21-5db1-a921-a37e-57729c1877d4', '2017-04-06 12:18:23', 1, '3d87bac4-49b0-3acb-3010-56684570afd9', '743cf2ca-e983-2f08-a2fb-5772966547a1'), 
 
('6d43042f-8f79-8d06-7d9e-58cf9bed69db', '2017-03-20 09:10:57', 1, '3d87bac4-49b0-3acb-3010-56684570afd9', '65730b79-3f6e-4385-c83e-58cf9b3a6cb4'), 
 
('6e8d9e2b-0300-4b67-b639-58cf9cc1d141', '2017-03-20 09:12:42', 1, '3d87bac4-49b0-3acb-3010-56684570afd9', '6e1bd69b-6501-95d5-1aa8-58cf9c44c529'), 
 
('70d706d1-ddba-1174-e73a-58cfd83ed1e5', '2017-04-06 12:18:23', 1, '3d87bac4-49b0-3acb-3010-56684570afd9', '705d3dad-8f77-04a6-05c5-58cfd8124fd5'), 
 
('7613bd00-0397-5b93-5aa9-57738ba67cca', '2016-06-29 08:47:35', 0, '3d87bac4-49b0-3acb-3010-56684570afd9', '7488d168-758c-f760-ed28-57738b5565db'), 
 
('78107ede-3f85-80f6-bad0-56718c341009', '2015-12-16 16:09:30', 0, 'eb914486-79d6-07e6-8263-566188671f7a', '760f5ee8-6470-9291-6733-56718c949974'), 
 
('790ba77f-4723-e52a-b991-58cf9c9da98c', '2017-03-20 09:12:42', 1, '3d87bac4-49b0-3acb-3010-56684570afd9', '788c0fcf-c454-c9fb-3af3-58cf9c82b7d3'), 
 
('81af0547-2f08-61d6-ed81-577b8160db2a', '2016-07-05 09:44:33', 0, 'c608ec6d-960e-eb4f-760d-577b81007df9', '80859612-d91f-bd91-8198-577b81c9dd09'), 
 
('852fc19f-2f48-942f-0ecc-58cf9c5abcc7', '2017-03-20 09:12:42', 1, '3d87bac4-49b0-3acb-3010-56684570afd9', '8462c635-7ccc-dc53-d152-58cf9c3d0222'), 
 
('87a6b49d-5943-4a26-7193-566aac243068', '2017-04-06 12:18:23', 1, '3d87bac4-49b0-3acb-3010-56684570afd9', '85bd5d08-110b-5bce-f564-566aac8ffa97'), 
 
('8aec1222-0b3e-b509-5801-58e63152154f', '2017-04-06 12:16:49', 0, '3d87bac4-49b0-3acb-3010-56684570afd9', '8a635f3b-9e0f-16aa-5532-58e631257729'), 
 
('936b09a7-3940-e350-6815-56616eeff1c5', '2015-12-04 10:43:35', 0, 'ce7c7bb1-c511-82e5-40bf-56616a7a10cc', '92a4c747-b1b7-2949-bcf6-56616ee3b065'), 
 
('9a2359bb-6fc9-ed44-7c81-58cfb514f537', '2017-03-20 13:26:13', 1, '3d87bac4-49b0-3acb-3010-56684570afd9', '999d63e2-67a7-b3a2-b236-58cfb505406b'), 
 
('9b3b1f2b-3e3e-30fe-e9a5-58cf9de1a73b', '2017-03-20 10:57:33', 1, '3d87bac4-49b0-3acb-3010-56684570afd9', '9aac98ea-703d-5aef-391d-58cf9d973ff2'), 
 
('9f230245-53e5-cd01-e775-577b8404ac60', '2016-07-05 09:58:43', 0, 'c608ec6d-960e-eb4f-760d-577b81007df9', '8c8404b6-4e53-5f2b-fcce-577b84f9dceb'), 
 
('9f97d432-9484-5417-7818-58e6352168ff', '2017-04-06 12:34:10', 0, 'ce7c7bb1-c511-82e5-40bf-56616a7a10cc', '9ecdc18e-9187-da7e-54d9-58e635cddf77'), 
 
('a2a1b248-dd8a-a7cd-fca6-56616e6c40c8', '2015-12-04 10:43:35', 0, 'ce7c7bb1-c511-82e5-40bf-56616a7a10cc', 'a2058842-e181-b794-6343-56616ef2e0b2'), 
 
('a680033e-316b-ef9b-0dde-58cf9d9c632a', '2017-03-20 10:57:33', 1, '3d87bac4-49b0-3acb-3010-56684570afd9', 'a5fc3006-fd64-e9dc-fb94-58cf9d5debdc'), 
 
('a81bbdd2-b462-b6d5-55a7-567673ca4ad5', '2015-12-20 09:25:15', 0, 'ce7c7bb1-c511-82e5-40bf-56616a7a10cc', 'a6c97a12-c6b4-f178-acc1-567673523d06'), 
 
('af0ef471-7dca-da91-6bc7-56616e9eb398', '2017-04-06 12:32:45', 1, 'ce7c7bb1-c511-82e5-40bf-56616a7a10cc', 'ae606f3d-5370-9abf-369a-56616e559357'), 
 
('af4cbeee-9f5a-d55a-5fbc-58cf9d6f385e', '2017-03-20 10:57:33', 1, '3d87bac4-49b0-3acb-3010-56684570afd9', 'aed7b370-1c60-2390-716c-58cf9d9f3d0c'), 
 
('b530b867-498a-bd70-65cc-58cfb526254b', '2017-03-20 13:26:13', 1, '3d87bac4-49b0-3acb-3010-56684570afd9', 'b4b53dca-3ca7-a5ad-84fd-58cfb507e8a0'), 
 
('b7d42855-3f4a-4bec-ada7-58cf9def096e', '2017-03-20 10:57:33', 1, '3d87bac4-49b0-3acb-3010-56684570afd9', 'b75a7e3a-3a04-e644-bbeb-58cf9de32173'), 
 
('ba70dbac-b9c4-b01a-ceb7-56616ef2ea42', '2017-04-06 12:32:45', 1, 'ce7c7bb1-c511-82e5-40bf-56616a7a10cc', 'b9d7250f-4971-05b8-ebe2-56616e43f6bc'), 
 
('c02eaa05-8b85-9af0-e9e8-58cfb53f574b', '2017-03-20 13:26:13', 1, '3d87bac4-49b0-3acb-3010-56684570afd9', 'bf7d328c-47d4-8d1c-bafe-58cfb5cc2d81'), 
 
('cb55beaf-b39f-8d78-c379-58cfb503c909', '2017-03-20 13:26:13', 1, '3d87bac4-49b0-3acb-3010-56684570afd9', 'cadc200c-4de2-9c78-f75a-58cfb5f67856'), 
 
('cd3a0876-9928-64ec-2d1f-566aab4e8926', '2015-12-11 10:56:48', 0, 'bb9311ed-8e1b-7715-9222-565f2e684b49', 'b15c0722-19da-79bf-51b2-566aabefc417'), 
 
('d24a2cd1-0922-9e67-3c8a-56616fa70aef', '2017-04-06 12:32:45', 1, 'ce7c7bb1-c511-82e5-40bf-56616a7a10cc', 'd203b35d-38b2-3d9c-1b46-56616f474d3c'), 
 
('d91d8d9d-6852-25e9-5f0b-56616f917b61', '2017-04-06 12:32:45', 1, 'ce7c7bb1-c511-82e5-40bf-56616a7a10cc', 'd8c9630e-4299-6767-e0c4-56616f979c7e'), 
 
('db20a6c0-30b6-87d4-dd8f-577b8154c1b5', '2016-07-05 09:44:04', 0, 'c608ec6d-960e-eb4f-760d-577b81007df9', 'd9fed2e5-a303-e3d6-0c0c-577b814f9e4c'), 
 
('de0951ca-9677-b28e-99a9-56616f275c90', '2017-04-06 12:32:45', 1, 'ce7c7bb1-c511-82e5-40bf-56616a7a10cc', 'ddc93703-d567-a464-22bc-56616f69224c'), 
 
('e4c778d6-5edf-a815-afb4-58cf9bc573f8', '2017-03-20 09:10:57', 1, '3d87bac4-49b0-3acb-3010-56684570afd9', 'e44fe420-a396-d951-cb7c-58cf9ba34f8a'), 
 
('e61ea6cf-aafc-b1d8-f7d8-56616ff24565', '2017-04-06 12:32:45', 1, 'ce7c7bb1-c511-82e5-40bf-56616a7a10cc', 'e5ce5ab1-2e65-2235-400e-56616fb9f5f6'), 
 
('e9c70b0c-f5d5-c08f-4249-58cf9a23ca90', '2017-03-20 09:03:40', 1, '3d87bac4-49b0-3acb-3010-56684570afd9', 'e1ce0b22-74ab-11e8-b4c8-58cf9a86acf8'), 
 
('ebe3092e-a344-00f4-8b5e-57728661f273', '2017-04-06 12:18:23', 1, '3d87bac4-49b0-3acb-3010-56684570afd9', 'c3d209bb-0a2b-a6a9-f215-5772867b4603'), 
 
('ee071730-fd54-a102-de1e-58cf9a9662fd', '2017-03-20 09:03:55', 1, '3d87bac4-49b0-3acb-3010-56684570afd9', 'ed65a8a5-f409-b7f2-c171-58cf9a17cc85'), 
 
('eee4ddd2-d929-838f-2527-58cf9bf35c6b', '2017-03-20 09:10:57', 1, '3d87bac4-49b0-3acb-3010-56684570afd9', 'ee7c27b6-9739-e6d0-7749-58cf9b82a093'), 
 
('f1470127-1225-5257-b1cc-58cf9bea895c', '2017-03-20 09:10:57', 1, '3d87bac4-49b0-3acb-3010-56684570afd9', 'e9f2030e-76f7-852e-3e7d-58cf9b407424'); 
 

 
-- -------------------------------------------------------- 
 

 
-- 
 
-- Struttura della tabella `tasks` 
 
-- 
 

 
CREATE TABLE IF NOT EXISTS `tasks` (
 
    `id` char(36) NOT NULL, 
 
    `name` varchar(50) DEFAULT NULL, 
 
    `date_entered` datetime DEFAULT NULL, 
 
    `date_modified` datetime DEFAULT NULL, 
 
    `modified_user_id` char(36) DEFAULT NULL, 
 
    `created_by` char(36) DEFAULT NULL, 
 
    `description` text, 
 
    `deleted` tinyint(1) DEFAULT '0', 
 
    `assigned_user_id` char(36) DEFAULT NULL, 
 
    `status` varchar(100) DEFAULT 'Not Started', 
 
    `date_due_flag` tinyint(1) DEFAULT '0', 
 
    `date_due` datetime DEFAULT NULL, 
 
    `date_start_flag` tinyint(1) DEFAULT '0', 
 
    `date_start` datetime DEFAULT NULL, 
 
    `parent_type` varchar(255) DEFAULT NULL, 
 
    `parent_id` char(36) DEFAULT NULL, 
 
    `contact_id` char(36) DEFAULT NULL, 
 
    `priority` varchar(100) DEFAULT NULL, 
 
    PRIMARY KEY (`id`), 
 
    KEY `idx_tsk_name` (`name`), 
 
    KEY `idx_task_con_del` (`contact_id`,`deleted`), 
 
    KEY `idx_task_par_del` (`parent_id`,`parent_type`,`deleted`), 
 
    KEY `idx_task_assigned` (`assigned_user_id`), 
 
    KEY `idx_task_status` (`status`) 
 
) ENGINE=InnoDB DEFAULT CHARSET=utf8 ROW_FORMAT=COMPACT; 
 

 
-- 
 
-- Dump dei dati per la tabella `tasks` 
 
-- 
 

 
INSERT INTO `tasks` (`id`, `name`, `date_entered`, `date_modified`, `modified_user_id`, `created_by`, `description`, `deleted`, `assigned_user_id`, `status`, `date_due_flag`, `date_due`, `date_start_flag`, `date_start`, `parent_type`, `parent_id`, `contact_id`, `priority`) VALUES 
 
('15c65e64-83d5-e27e-9ded-56efc6034ec7', 'c1lesson1', '2016-03-21 10:02:12', '2017-04-06 12:18:23', '1', '1', NULL, 1, '1', 'Completed', 0, '2016-03-18 10:45:00', 0, '2016-03-18 10:00:00', NULL, '', '', 'High'), 
 
('16ce0346-064f-c93e-19ca-5668427c30b4', 'c2lesson_first_completed', '2015-12-09 15:03:11', '2017-04-06 12:29:16', '1', '1', NULL, 0, '1', 'Completed', 0, '2015-12-10 11:00:00', 0, '2015-12-10 10:00:00', NULL, '', '', 'High'), 
 
('18f60d90-0554-4880-760b-5668455dd961', 'c5lesson1', '2015-12-09 15:16:30', '2017-04-06 12:36:42', '1', '1', NULL, 0, '1', 'Not Started', 0, '2015-12-12 11:00:00', 0, '2015-12-12 10:00:00', NULL, '', '', 'High'), 
 
('226c2475-16a3-e0af-efaa-5671a483f0e2', 'nocourse_lesson2', '2015-12-16 17:52:23', '2017-04-06 12:40:24', '1', '1', NULL, 0, '1', 'Not Started', 0, '2015-12-17 11:00:00', 0, '2015-12-17 10:00:00', NULL, '', '', 'High'), 
 
('2996ca74-f2d5-a0bf-0c92-56616d7db8d4', 'c4lesson3', '2015-12-04 10:41:15', '2017-04-06 12:34:36', '1', 'c0aa6b17-16d0-baea-c4ae-566162ba3706', NULL, 0, 'c0aa6b17-16d0-baea-c4ae-566162ba3706', 'Completed', 0, '2015-10-05 09:30:00', 0, '2015-10-05 08:45:00', NULL, '', '', 'High'), 
 
('2f19dd24-1c2f-a245-1856-566b214d7abd', 'c1lesson_last_completed', '2015-12-11 19:16:20', '2017-04-06 12:26:34', '1', '1', NULL, 0, '1', 'Completed', 0, '2015-12-16 11:00:00', 0, '2015-12-16 10:00:00', NULL, '', '', 'High'), 
 
('39109517-1f24-8048-4fca-56616e12fc48', 'c4lesson4', '2015-12-04 10:45:59', '2017-04-06 12:35:11', '1', 'c0aa6b17-16d0-baea-c4ae-566162ba3706', NULL, 0, 'c0aa6b17-16d0-baea-c4ae-566162ba3706', 'Completed', 0, '2015-10-08 09:30:00', 0, '2015-10-08 08:45:00', NULL, '', '', 'High'), 
 
('3b0e7a1e-543c-ea43-5a5c-565ee2d8a787', 'GWENT - VR', '2015-12-02 12:20:48', '2017-04-06 12:39:20', '1', 'e07880a3-a57d-a20c-9e25-565eb7af093f', NULL, 0, '36fcf0ba-7cd8-1195-2825-5655fd33eabd', 'Not Started', 0, '2015-10-14 11:30:00', 0, '2015-10-14 10:45:00', NULL, '', '', 'High'), 
 
('3d62fc14-f606-a737-d76c-565ee38e767b', 'GWENT - VR', '2015-12-02 12:28:27', '2017-04-06 12:39:20', '1', 'e07880a3-a57d-a20c-9e25-565eb7af093f', NULL, 1, '36fcf0ba-7cd8-1195-2825-5655fd33eabd', 'Not Started', 0, '2015-10-23 11:30:00', 0, '2015-10-23 10:45:00', NULL, '', '', 'High'), 
 
('4dd39006-f652-3ae1-d6a6-56718c46617e', 'maghull test 2', '2015-12-16 16:09:01', '2017-04-06 12:37:27', '1', '1', NULL, 1, '1', 'Not Started', 0, '2015-12-12 11:00:00', 0, '2015-12-12 10:00:00', NULL, '', '', 'High'), 
 
('595a2e58-76bc-c134-3cef-58e64b59e8d5', 'c1lesson_last_completed', '2017-04-06 14:08:03', '2017-03-16 14:09:28', '1', '1', NULL, 0, '1', 'Completed', 0, '2015-12-16 11:00:00', 0, '2015-12-16 10:00:00', NULL, '', '', 'High'), 
 
('5ba36af1-8f2b-075b-926f-58cfd87a83e7', 'c1lesson_notyetcompleted', '2017-03-20 13:26:40', '2017-04-06 12:27:12', '1', '1', NULL, 0, 'a691ed76-ef37-ad18-4450-561397563eee', 'Not Started', 1, NULL, 1, NULL, NULL, '', '', 'High'), 
 
('6693cd37-0b74-1d97-c395-5672a343260d', 'nocourse_lesson1', '2015-12-17 11:59:11', '2017-04-06 12:39:59', '1', '1', NULL, 0, '1', 'Completed', 0, '2015-12-18 15:00:00', 0, '2015-12-18 14:00:00', NULL, '', '', 'High'), 
 
('7488d168-758c-f760-ed28-57738b5565db', 'c1lesson1', '2016-06-29 08:47:35', '2017-04-06 12:15:28', '1', '1', NULL, 0, '1', 'Completed', 0, '2015-04-06 09:45:00', 0, '2015-04-06 09:00:00', NULL, '', '', 'High'), 
 
('760f5ee8-6470-9291-6733-56718c949974', 'c5lesson2', '2015-12-16 16:09:30', '2017-04-06 12:37:50', '1', '1', NULL, 0, '1', 'Not Started', 0, '2015-12-14 11:00:00', 0, '2015-12-14 10:00:00', NULL, '', '', 'High'), 
 
('80859612-d91f-bd91-8198-577b81c9dd09', 'c3lesson2', '2016-07-05 09:44:33', '2017-04-06 12:24:08', '1', '1', NULL, 0, '1', 'Completed', 1, NULL, 0, '2016-07-05 09:00:00', NULL, '', '', 'High'), 
 
('8a635f3b-9e0f-16aa-5532-58e631257729', 'c1lesson_first_completed', '2017-04-06 12:16:49', '2017-04-06 12:27:36', '1', '1', NULL, 0, '1', 'Completed', 0, '2015-04-06 09:45:00', 0, '2015-04-06 09:00:00', NULL, '', '', 'High'), 
 
('8c8404b6-4e53-5f2b-fcce-577b84f9dceb', 'c3lesson_last_completed', '2016-07-05 09:58:43', '2017-04-06 12:31:22', '1', '1', NULL, 0, '1', 'Completed', 1, NULL, 0, '2016-07-06 09:00:00', NULL, '', '', 'High'), 
 
('92a4c747-b1b7-2949-bcf6-56616ee3b065', 'c4lesson2', '2015-12-04 10:43:35', '2017-04-06 12:33:52', '1', 'c0aa6b17-16d0-baea-c4ae-566162ba3706', NULL, 0, 'a691ed76-ef37-ad18-4450-561397563eee', 'Completed', 0, '2015-10-04 09:30:00', 0, '2015-10-04 08:45:00', NULL, '', '', 'High'), 
 
('9ecdc18e-9187-da7e-54d9-58e635cddf77', 'c4lesson2', '2017-04-06 12:34:10', '2017-04-06 12:34:10', '1', '1', '', 0, 'a691ed76-ef37-ad18-4450-561397563eee', 'Not Started', 0, '2015-10-04 09:30:00', 0, '2015-10-04 08:45:00', NULL, NULL, NULL, 'High'), 
 
('a2058842-e181-b794-6343-56616ef2e0b2', 'c4lesson4_last_completed', '2015-12-04 10:43:35', '2017-04-06 12:35:49', '1', 'c0aa6b17-16d0-baea-c4ae-566162ba3706', NULL, 0, 'a691ed76-ef37-ad18-4450-561397563eee', 'Not Started', 0, '2015-10-19 09:30:00', 0, '2015-10-19 08:45:00', NULL, '', '', 'High'), 
 
('a6c97a12-c6b4-f178-acc1-567673523d06', 'c4lesson_first_completed', '2015-12-20 09:25:15', '2017-04-06 12:33:24', '1', '1', NULL, 0, '1', 'Completed', 0, '2015-07-02 09:00:00', 0, '2015-07-02 09:00:00', NULL, '', '', 'High'), 
 
('b15c0722-19da-79bf-51b2-566aabefc417', 'c2lesson_last_completed', '2015-12-11 10:56:48', '2017-04-06 12:29:58', '1', '1', NULL, 0, '1', 'Completed', 0, '2015-12-16 11:00:00', 0, '2015-12-16 10:00:00', NULL, '', '', 'High'), 
 
('d9fed2e5-a303-e3d6-0c0c-577b814f9e4c', 'c3lesson_first_completed', '2016-07-05 09:44:04', '2017-04-06 12:30:54', '1', '1', NULL, 0, '1', 'Completed', 1, NULL, 0, '2016-07-01 09:00:00', NULL, '', '', 'High'), 
 
('fb94089f-57e9-0918-c98f-56756fa424d4', 'c1lesson2', '2015-12-19 14:55:56', '2017-04-06 12:17:29', '1', '1', NULL, 0, '1', 'Completed', 0, '2015-10-06 09:00:00', 0, '2015-10-06 09:00:00', NULL, '', '', 'High'); 
 

 
/*!40101 SET [email protected]_CHARACTER_SET_CLIENT */; 
 
/*!40101 SET [email protected]_CHARACTER_SET_RESULTS */; 
 
/*!40101 SET [email protected]_COLLATION_CONNECTION */;

用下面的查詢，我能夠得到的所有「完成」的教訓名單，但我惹上麻煩只需每月每門課程......最近一個在實踐中我需要在第一行，每門課程：

我不是一個SQL專家，我真的很感激任何幫助。謝謝。
Piergiorgio

SELECT pj001_courses.name AS Corso, 
 
     pj001_courses.id AS id_corso, 
 
     tasks.id AS idlez, 
 
     tasks.name AS Lezione, 
 
     tasks.date_modified AS date_modified, 
 
     max_dates.max_date_start AS date_start 
 
FROM pj001_courses 
 
JOIN pj001_courses_tasks_c ON pj001_courses.id = pj001_courses_tasks_c.pj001_courses_taskspj001_courses_ida 
 
JOIN tasks ON pj001_courses_tasks_c.pj001_courses_taskstasks_idb = tasks.id 
 
JOIN (SELECT pj001_courses_tasks_c.pj001_courses_taskspj001_courses_ida AS id_corso, 
 
       MAX(tasks.date_start) AS max_date_start 
 
     FROM pj001_courses_tasks_c 
 
     JOIN tasks ON pj001_courses_tasks_c.pj001_courses_taskstasks_idb = tasks.id 
 
     WHERE pj001_courses_tasks_c.deleted = 0 
 
     AND tasks.deleted = 0 
 
     AND tasks.status = 'completed' 
 
     GROUP BY id_corso) max_dates ON max_dates.id_corso = pj001_courses.id 
 
            AND max_dates.max_date_start = tasks.date_start 
 
WHERE pj001_courses.deleted = 0 
 
ORDER BY Corso, 
 
     id_corso, 
 
     tasks.date_start DESC, 
 
     tasks.date_modified desc;

來源

2017-04-05 Piergiorgio

爲什麼GROUP BY時，沒有聚集功能涉及？ – jarlh

你是否需要'status'作爲輸出的一部分？ – toonice

兩個課程可以有相同的名稱嗎？兩個任務可以有相同的ID或名稱嗎？ – toonice

請嘗試...

SELECT pj001_courses.name AS Corso, 
     pj001_courses.id AS id_corso, 
     tasks.id AS idlez, 
     tasks.name AS Lezione, 
     tasks.date_modified AS date_modified, 
     tasks.date_start AS date_start 
FROM pj001_courses 
JOIN pj001_courses_tasks_c ON pj001_courses.id = pj001_courses_tasks_c.pj001_courses_taskspj001_courses_ida 
JOIN tasks ON pj001_courses_tasks_c.pj001_courses_taskstasks_idb = tasks.id 
JOIN 
(
    SELECT pj001_courses_tasks_c.pj001_courses_taskspj001_courses_ida AS id_corso, 
      tasks.date_start AS max_date_start, 
      MAX(tasks.date_modified) AS max_date_modified 
    FROM pj001_courses_tasks_c 
    JOIN tasks ON pj001_courses_tasks_c.pj001_courses_taskstasks_idb = tasks.id 
    WHERE (pj001_courses_tasks_c.pj001_courses_taskspj001_courses_ida, 
      tasks.date_start) IN (SELECT pj001_courses_tasks_c.pj001_courses_taskspj001_courses_ida AS id_corso, 
              MAX(tasks.date_start) AS max_date_start 
            FROM pj001_courses_tasks_c 
            JOIN tasks ON pj001_courses_tasks_c.pj001_courses_taskstasks_idb = tasks.id 
            WHERE pj001_courses_tasks_c.deleted = 0 
             AND tasks.deleted = 0 
             AND tasks.status = 'completed' 
            GROUP BY id_corso 
           ) 
    GROUP BY id_corso 
) max_dates_finder ON pj001_courses.id = max_dates_finder.id_corso 
        AND tasks.date_start = max_dates_finder.max_date_start 
        AND tasks.date_modified = max_dates_finder.max_date_modified 
WHERE pj001_courses.deleted = 0 
ORDER BY Corso, 
     id_corso;

下段產生，其中該單位已經完成，尚未分配到每個課程單元的列表從課程中刪除或一般刪除。然後輸出每門課程的id和最近值date_start。

SELECT pj001_courses_tasks_c.pj001_courses_taskspj001_courses_ida AS id_corso, 
     MAX(tasks.date_start) AS max_date_start 
FROM pj001_courses_tasks_c 
JOIN tasks ON pj001_courses_tasks_c.pj001_courses_taskstasks_idb = tasks.id 
WHERE pj001_courses_tasks_c.deleted = 0 
    AND tasks.deleted = 0 
    AND tasks.status = 'completed' 
GROUP BY id_corso

以下段產生課程的列表，並分配給其中每個條目的過程id和date_start出現在通過先前的段生成的列表中的每個過程的那些單元。那麼這個新的列表被細化到剛剛課程id，最近的date_start該課程和date_modified對應的date_start該值的最新值值。

SELECT pj001_courses_tasks_c.pj001_courses_taskspj001_courses_ida AS id_corso, 
     tasks.date_start AS max_date_start, 
     MAX(tasks.date_modified) AS max_date_modified 
FROM pj001_courses_tasks_c 
JOIN tasks ON pj001_courses_tasks_c.pj001_courses_taskstasks_idb = tasks.id 
WHERE (pj001_courses_tasks_c.pj001_courses_taskspj001_courses_ida, 
     tasks.date_start) IN (SELECT pj001_courses_tasks_c.pj001_courses_taskspj001_courses_ida AS id_corso, 
             MAX(tasks.date_start) AS max_date_start 
           FROM pj001_courses_tasks_c 
           JOIN tasks ON pj001_courses_tasks_c.pj001_courses_taskstasks_idb = tasks.id 
           WHERE pj001_courses_tasks_c.deleted = 0 
            AND tasks.deleted = 0 
            AND tasks.status = 'completed' 
           GROUP BY id_corso 
          ) 
GROUP BY id_corso

此代碼然後JOIN版與其他表和細化，只有那些沒有被刪除，從我的答案開始產生代碼的課程。

如果您有任何問題或意見，請隨時發佈相應評論。

來源

2017-04-05 08:06:46 toonice

按Enter鍵完成註釋而不是行。 – toonice

嗨toonice，謝謝你的回答。關於您的問題：1）輸出中不需要狀態。對不起。 2）課程可以具有相同的名稱但不是相同的ID，3）任務可以具有相同的名稱，但是不具有相同的ID。 3）tasks.date_start和date_modified都是日期時間數據類型。我包含'date_modified'是因爲將數據查看到數據庫中，我意識到在名稱和date_start方面存在一些重複的任務，所以我假設最後修改的是好的。 – Piergiorgio

我試過了你的查詢，但是我的msqlfront給出了「錯誤sql＃1052。列'date_modified'where子句不明確。」 – Piergiorgio

@toonice最後一個查詢中的某些字段名稱不正確。我修正了它們，但無論如何，結果看起來不一致。 DATE_START和date_modified.I'm新在這裏堆棧溢出，不知道我是否可以將只四十零分之三十〇記錄查詢測試purpouse測試數據庫

SELECT pj001_courses.name AS Corso, 
 
     pj001_courses.id AS id_corso, 
 
     tasks.id AS idlez, 
 
     tasks.name AS Lezione, 
 
     tasks.date_start AS date_start, 
 
     MAX(tasks.date_modified) AS date_modified 
 
FROM pj001_courses 
 
JOIN pj001_courses_tasks_c ON pj001_courses.id = pj001_courses_tasks_c.pj001_courses_taskspj001_courses_ida 
 
JOIN tasks ON pj001_courses_tasks_c.pj001_courses_taskstasks_idb = tasks.id 
 
WHERE tasks.deleted = 0 
 
    AND tasks.status = 'completed' 
 
    AND pj001_courses.deleted = 0 
 
GROUP BY id_corso 
 
ORDER BY Corso, 
 
     id_corso, 
 
     tasks.date_start DESC, 
 
     tasks.id;

來源

2017-04-06 12:05:30 Piergiorgio

如果您可以修改您的問題以包含用於創建表格和填充示例數據的腳本，將會非常有幫助。你能創建這樣一個腳本嗎？ – toonice

@toonice，我修改了我的問題，包括一個數據庫創建腳本和我創建的查詢腳本作爲出發點以獲取不期望的結果。讓我知道如果一切都可以重新創建我的測試環境。 – Piergiorgio

我已經開始測試您的示例數據。在回顧'tasks'後，我發現與'id = 5ba36af1-8f2b-075b-926f-58cfd87a83e7'相關的'date_start'值是'NULL'。這應該是這樣嗎？另外，在像'description'，'parent_id'和'contact_id'這樣的列中，你可以使用'NULL'並且有時使用'''''。作爲一個良好的做法，我建議你將標準化爲「NULL」。 – toonice

如何通過最近的日期在3臺SQL查詢

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