mysql

问题 I can't get this query to work! return Post::selectRaw('likes_count + comments_count as total_count') ->withCount(['likes', 'comments']) ->groupBy('posts.id') ->orderByDesc('total_count') ->paginate(); It works this way below but I want all the counts and something performant! return Post::leftJoin('likes', function ($join) { $join->on('posts.id', 'likes.likable_id') ->where('likes.likable_type', (new Post)->getMorphClass()); })->leftJoin('comments', function ($join) { $join->on('posts.id',

问题 I use mysql.connector to fetch rows in a python script but when I update a table the I don't see the changes. My code is: import mysql.connector database = mysql.connector.connect(host='localhost', user='root', passwd='password', database='my_db') cursor = database.cursor() cursor.execute('SELECT * FROM my_table') print(cursor.fetchall()) cursor.execute('SELECT * FROM my_table') print(cursor.fetchall()) In first time it reads the correct values but at the second time it reads the same values

问题 I have data stored in two different tables called "posts" and "comments". Now i'm using two mysqli_query. $q = mysqli_query($db,"SELECT * FROM posts WHERE username='$username'"); $q = mysqli_query($db,"SELECT * FROM comments WHERE username='$username'"); Can I make this with only one mysqli_query or with 3 tables? 回答1: You can simply join both tables: $q = mysqli_query($db,"SELECT * FROM posts LEFT JOIN comments ON comments.username=posts.username WHERE comments.username='$username'");

问题 how i use MySQL function JSON_SEARCH on all values, not only on strings? All this bug is documented on MySQL emulator: https://www.db-fiddle.com/f/2UdrxqrQ3DeonbKWw3pVVp/0 I have DDL: CREATE TABLE table_name ( id int NOT NULL AUTO_INCREMENT, json_config JSON, PRIMARY KEY (id) ); INSERT INTO table_name (id,json_config) VALUES (NULL, '{ "_id": "60111111111111175b78fe2fa", "intestx": 0, "codes": [ 48348, 28923, 39080 ], "test": 562222222222456 }'); Query #1: SELECT JSON_SEARCH(json_config, 'all'

问题 how i use MySQL function JSON_SEARCH on all values, not only on strings? All this bug is documented on MySQL emulator: https://www.db-fiddle.com/f/2UdrxqrQ3DeonbKWw3pVVp/0 I have DDL: CREATE TABLE table_name ( id int NOT NULL AUTO_INCREMENT, json_config JSON, PRIMARY KEY (id) ); INSERT INTO table_name (id,json_config) VALUES (NULL, '{ "_id": "60111111111111175b78fe2fa", "intestx": 0, "codes": [ 48348, 28923, 39080 ], "test": 562222222222456 }'); Query #1: SELECT JSON_SEARCH(json_config, 'all'

问题 EXPLAIN EXTENDED SELECT * FROM table_name -- FORCE INDEX(dummy_date) USE INDEX(dummy_date) where dummy_date between '2020-12-01' AND '2020-12-31' AND name='something'; ALTER TABLE `table_name` ADD INDEX `dummy_date_index`(`dummy_date`) When I execute this query then indexing is not working but if I use force index then its working with index. Please let me know the correct approach to use the index for millions of rows. 回答1: Even better than MySQL not using indexes with WHERE IN clause? --

问题 I had tried to add or remove the '@' before variables or params but nothing happened. QUERY start transaction; set @recordClient = (select ClientId from by_test_db1.recordcd where SN = 'abc' ); set @logClient = (select ClientId from by_test_db1.log where SN = 'abc' ); select concat(@recordClient,@logClient); commit; SP delimiter $$ create procedure TEST(newSN varchar(50)) begin start transaction; set @recordClient = (select ClientId from by_test_db1.recordcd where SN = newSN ); set @logClient

问题 I have a form where I want a user to enter one or more words. These words should then match mutiple columns in a MySQL database. I have started to build some code but I'm stuck. <?php $term = $_SESSION['session_searchstring']; //Let's say that session is John Doe $searchterm = explode(' ',$term); $searchFieldName = "name"; $searchCondition = "$searchFieldName LIKE '%" . implode("%' OR $searchFieldName LIKE '%", $searchterm) . "%'"; $sql = "SELECT * FROM students WHERE $searchCondition;"; echo

问题 I have a form where I want a user to enter one or more words. These words should then match mutiple columns in a MySQL database. I have started to build some code but I'm stuck. <?php $term = $_SESSION['session_searchstring']; //Let's say that session is John Doe $searchterm = explode(' ',$term); $searchFieldName = "name"; $searchCondition = "$searchFieldName LIKE '%" . implode("%' OR $searchFieldName LIKE '%", $searchterm) . "%'"; $sql = "SELECT * FROM students WHERE $searchCondition;"; echo

问题 What solutions are there for making a simple connection to a MySQL database in C++? I find MySQL Connector from dev.mysql.com hard to integrate. Anticipated thanks! 回答1: Its pretty simple to communicate with MySQL from C/C++ application you need to include mysql.h header file three basic APIs to connect and execute query mysql_connect() mysql_query() mysql_close() Link with mysql library (libMysql) 回答2: You could try the ODBC path, with a support library. Some year ago I used OTL to interface