Manual:MySQL/Start

 mysql -u wikiuser -p my_wiki

Change wikiuser and my_wiki to the username and database name for your wiki ($wgDBuser and $wgDBname ). When prompted, enter your password.

Example

edit
$ mysql -u root -p my_wiki
Enter password: 
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 150
Server version: 5.6.24-0ubuntu2 (Ubuntu)
...

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

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