From Save MySQL query results into a text or CSV file: Note: That syntax may need to be reordered to in more recent versions of MySQL. Using this command, columns names will not be exported. Also note that /var/lib/mysql-files/orders.csv will be on the server that is running MySQL. The user that the MySQL process is running under must have permissions … Read more
Starting in SQL Server 2017 the STRING_AGG function is available which simplifies the logic considerably: See SQL Fiddle with Demo In SQL Server you can use FOR XML PATH to get the result: See SQL Fiddle with Demo
Just found it, it is /etc/my.cnf
Update: These articles in my blog describe the differences between the methods in more detail: NOT IN vs. NOT EXISTS vs. LEFT JOIN / IS NULL: SQL Server NOT IN vs. NOT EXISTS vs. LEFT JOIN / IS NULL: PostgreSQL NOT IN vs. NOT EXISTS vs. LEFT JOIN / IS NULL: Oracle NOT IN vs. NOT EXISTS vs. LEFT JOIN / IS NULL: MySQL There are three ways to do such a query: LEFT JOIN … Read more
An INNER JOIN can return data from the columns from both tables, and can duplicate values of records on either side have more than one match. A LEFT SEMI JOIN can only return columns from the left-hand table, and yields one of each record from the left-hand table where there is one or more matches in the right-hand table … Read more
from command line you can use: http://dev.mysql.com/doc/refman/5.0/en/mysqlcheck.html
That would have to be: Or, similar: You’re looking for something that contains “m” somewhere (SQL’s ‘%‘ operator is equivalent to regular expressions’ ‘.*‘), not something that has “m” anchored to the beginning of the string. Note: MongoDB uses regular expressions which are more powerful than “LIKE” in SQL. With regular expressions you can create any … Read more
You can do something like this: See, for example: https://dev.mysql.com/doc/refman/5.0/en/union.html
What is a LATERAL join? The feature was introduced with PostgreSQL 9.3. The manual: Subqueries appearing in FROM can be preceded by the key word LATERAL. This allows them to reference columns provided by preceding FROM items. (Without LATERAL, each subquery is evaluated independently and so cannot cross-reference any other FROM item.) Table functions appearing in FROM can also be preceded by the key word LATERAL, but for functions the key … Read more
A database is generally used for storing related, structured data, with well defined data formats, in an efficient manner for insert, update and/or retrieval (depending on application). On the other hand, a file system is a more unstructured data store for storing arbitrary, probably unrelated data. The file system is more general, and databases are … Read more