7/27/2023 0 Comments Mysql database server tutorialSo, instead of this: select * from information_schema.tables where table_name like 'wp_%' ĭo this: SELECT * FROM information_schema.tables WHERE table_name LIKE 'wp_%' Avoid Using SELECT *Īvoid using SELECT * in your SQL queries. This makes your code more readable and less susceptible to errors. When writing SQL code, always use uppercase for SQL keywords and lowercase for table names and column names. Here are some other best practices to keep in mind. Be sure to cross-check your syntax as well. To avoid this, cross-check the table or column name to ensure it is spelled correctly. One of the most common causes of errors when executing SQL is the failure to use a semicolon at the end of statements.Īnother is using an invalid SQL syntax or an incorrectly spelled table/column name. Other tables found in information_schema include columns, constraints, table_constraints, check_constraints, and referential_constraints. The results of the schema information of only the WordPress tables. Similarly, you can perform a query to retrieve only the tables that match a specified pattern.įor example, the following query returns the schema information of only the WordPress tables - only the tables whose names start with “wp_”: SELECT * FROM information_schema.tables WHERE table_name LIKE 'wp_%' In addition, you have the tables table from the information_schema database, which contains information about all tables. For database filtering, you can perform a complex search to query the schema table for specific databases.įor example, if you want databases whose names start with either “samp” or “word,” you can combine several other clauses to make a complex query: SELECT schema_name FROM information_schema.schemata WHERE schema_name LIKE 'samp%' OR schema_name LIKE 'word%' The information_schema database makes use of the schemata table to store information about all databases. Using Information Schema to Query Table MetadataĮarlier, you saw how the information_schema database stores all the information related to databases, tables, and other objects in the MySQL server environment. The filtered database response when using ‘w%’. The string must end with the percentage symbol, %, which denotes one or more characters.įor example, if you want to display just the databases whose names start with the letter w, you do so by running the following: SHOW DATABASES LIKE 'w%' It must be a string representing the pattern you want to match. Here’s the general syntax: SHOW DATABASES LIKE '' The LIKE clause filters the result of SHOW DATABASE based on a specified pattern. Previously, you returned all of the databases on the MySQL server with SHOW DATABASES, but you often have to filter the database output, mainly when there are many databases on the server. The information_schema database is a non-modifiable database that stores all the information related to databases and other objects (views, user privileges, tables, constraints, etc.) stored in the MySQL server. Out of the six databases returned, information_schema and performance_schema are the default databases that are automatically generated when you install MySQL. In return, you get all the databases present in the storage: Now that you’re logged in, you can list MySQL databases present in the server by executing the SHOW DATABASES command: SHOW DATABASES The default username for MySQL is root, and the password is empty (there’s no password by default). Make sure your MySQL server is running before logging in via the command prompt: mysql -u -p To list MySQL databases, the user must be authorized to access all databases, or you must set a global SHOW DATABASES privilege that grants access to all users. Now that the path has been added, you can execute MySQL commands in the terminal. Next, click New and paste the full path to your MySQL executable (which you copied earlier). Then, click Environment Variables under Startup and Recovery, select the PATH variable and click Edit. For WAMP, navigate through > bin to its full path.Ĭlick the Start menu and search for “path.” Click Edit the system environment variable. If you’re running XAMPP, navigate to xampp > mysql > bin and copy the full path to the bin folder. Click the drive where you’ve installed the WAMP or XAMPP package ( C:). Uncover performance bottlenecks to deliver a better user experience and hit your business’s revenue goals.įirst, launch your Windows file explorer and navigate to This PC.
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