Yes, you can reuse variables. This is how you do it: SELECT @total_sale := s.f1 + s.f2 as total_sale, s.f1 / @total_sale as f1_percent FROM sales s Read more about it here: http://dev.mysql.com/doc/refman/5.0/en/user-variables.html [Note: This behavior is undefined. According to the MySQL docs:] As a general rule, you should never assign a value to a … Read more
From the now unavailable internet archive: Go to Edit -> Preferences -> SQL Editor and set to a higher value this parameter: DBMS connection read time out (in seconds). For instance: 86400. Close and reopen MySQL Workbench. Kill your previously query that probably is running and run the query again.
So the question is are there any techniques for speeding up these kinds of queries? Well, not really. A column-based storage engine would probably be faster with those SELECT COUNT(*) queries but it would be less performant for pretty much any other query. Your best bet is to maintain a summary table via triggers. It … Read more
version: “2.1” services: api: build: . container_name: api ports: – “8080:8080” depends_on: db: condition: service_healthy db: container_name: db image: mysql ports: – “3306” environment: MYSQL_ALLOW_EMPTY_PASSWORD: “yes” MYSQL_USER: “user” MYSQL_PASSWORD: “password” MYSQL_DATABASE: “database” healthcheck: test: [“CMD”, “mysqladmin” ,”ping”, “-h”, “localhost”] timeout: 20s retries: 10 The api container will not start until the db container is healthy … Read more
It will return 18 results starting on record #9 and finishing on record #26. Start by reading the query from offset. First you offset by 8, which means you skip the first 8 results of the query. Then you limit by 18. Which means you consider records 9, 10, 11, 12, 13, 14, 15, 16….24, … Read more
Sounds like you have Schroedinger’s table… Seriously now, you probably have a broken table. Try: DROP TABLE IF EXISTS contenttype REPAIR TABLE contenttype If you have sufficient permissions, delete the data files (in /mysql/data/db_name)
as mentioned in the responses above, it could be related to AWS security groups, and other things. but if you created a user and gave it remote access ‘%’ and still getting this error, check your mysql config file, on debian, you can find it here: /etc/mysql/my.cnf and find the line: bind-address = 127.0.0.1 and … Read more
Yes, it depends on the situation you are in. Why use SQL JOIN? Answer: Use the SQL JOIN whenever multiple tables must be accessed through an SQL SELECT statement and no results should be returned if there is not a match between the JOINed tables. Reading this original article on The Code Project will help … Read more
First, I can give you the answer for one table: The trouble with all these INTO OUTFILE or –tab=tmpfile (and -T/path/to/directory) answers is that it requires running mysqldump on the same server as the MySQL server, and having those access rights. My solution was simply to use mysql (not mysqldump) with the -B parameter, inline … Read more
utf8_general_ci is a very simple — and on Unicode, very broken — collation, one that gives incorrect results on general Unicode text. What it does is: converts to Unicode normalization form D for canonical decomposition removes any combining characters converts to upper case This does not work correctly on Unicode, because it does not understand … Read more