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Repair MyISAM Tables in MySQL
How To Check and Repair MyISAM Tables in MySQL? If you have a corrupted MyISAM table, like the one resulted from the previous tutorial exercise, you can use the "CHECK TABLE" and "REPAIR TABLE" commands to try to repair it. The following tutorial exercise gives you a good example of repairing a corr...
2017-09-01, 782👍, 0💬

Shutdown the Server with "mysqladmin" Command in MySQL
How To Shut Down the Server with "mysqladmin" in MySQL? If you want to shut down the server with "mysqladmin", you can use the command "mysqladmin shutdown" as shown in the following tutorial example: &gt;cd \mysql\bin &gt;mysqladmin -u root shutdown If this command returns no messages, your...
2018-06-01, 780👍, 0💬

Dump a Table to a File with "mysqldump" Command in MySQL
How To Dump a Table to a File with "mysqldump" in MySQL? If you want to dump all rows in a table from the server to a file, you can use "mysqldump" with the "-f fileName" option as show in the following tutorial exercise: &gt;cd \mysql\bin &gt;mysqldump -u root -r \temp\links.txt test links ...
2018-05-19, 780👍, 0💬

Show Server Status with "mysqladmin" in MySQL
How To Check Server Status with "mysqladmin" in MySQL? If you want to check the server status by with "mysqladmin", you can following this tutorial example: &gt;cd \mysql\bin &gt;mysqladmin -u root status Uptime: 223 Threads: 1 Questions: 1 Slow queries: 0 Opens: 12 Flush tables: 1 Open tabl...
2018-06-01, 778👍, 0💬

Entering Characters as HEX Numbers in MySQL
How To Enter Characters as HEX Numbers in MySQL? If you want to enter characters as HEX numbers, you can quote HEX numbers with single quotes and a prefix of (X), or just prefix HEX numbers with (0x). A HEX number string will be automatically converted into a character string, if the expression cont...
2018-03-31, 778👍, 0💬

Tables Using CSV Storage Engine in MySQL
How To Create a New Table Using the CSV Storage Engine in MySQL? CSV (Comma-Separated Values) storage engine stores table data in text files in comma-separated value format. CSV is not the default storage engine. You need to specify "ENGINE = CSV" at the end of the "CREATE TABLE" statement to create...
2017-08-13, 777👍, 0💬

Show All Indexes of a given Table in MySQL
How To Get a List of Indexes of a Given Table in MySQL? If you want to see the index you have just created for an existing table, you can use the "SHOW INDEX FROM tableName" command to get a list of all indexes in a given table. The tutorial script below shows you a nice example: mysql&gt; SHOW ...
2018-02-14, 775👍, 0💬

What Is "mysql" Command in MySQL
What Is "mysql" in MySQL? "mysql" is a command-line interface for end users to manage user data objects. You can use "mysql" to run any standard SQL statements against the server. For example, you use the following SQL statements to manage tables and table rows: "CREATE TABLE links (name VARCHAR(80)...
2018-05-19, 774👍, 0💬

What Is MySQL
What Is MySQL? MySQL is an open source database management system developed by MySQL AB, http://www.mysql.com.   ⇒Database Basics and Terminologies in MySQL ⇒⇒MySQL Database Tutorials
2017-07-21, 773👍, 0💬

Calculating the Difference between Two Time Values in MySQL
How To Calculate the Difference between Two Time Values in MySQL? If you have two time values, and you want to know the time difference between them, you can use the TIMEDIFF(time1, time2) function as shown below: SELECT TIMEDIFF(TIME('19:26:50'), TIME('09:26:50')) FROM DUAL; 10:00:00 SELECT TIMEDIF...
2017-12-26, 772👍, 0💬

Quoting Date and Time Values in MySQL
How To Quote Date and Time Values in SQL Statements in MySQL? If you want to provide date and time values in a SQL statement, you should write them in the format of "yyyy-mm-dd hh:mm:ss", and quoted with single quotes ('). The tutorial exercise below shows you two INSERT statements. The first one us...
2017-06-23, 770👍, 0💬

Omitting Columns in INSERT Statements in MySQL
How To Omit Columns with Default Values in INSERT Statement in MySQL? If you don't want to specify values for columns that have default values, or you want to specify values to columns in an order different than how they are defined, you can provide a column list in the INSERT statement. If a column...
2018-01-16, 769👍, 0💬

Giving Privileges at Server Level in MySQL
How To Grant User Privileges at the Global Level in MySQL? If you want to grant a user privilege at the global level, you can use the "GRANT privilegeName ON *.* TO userName" command. The argument "*.*" in the command stands for all database and all tables. The following tutorial exercise shows you ...
2017-08-21, 769👍, 0💬

Transaction Roll Back when Session Killed in MySQL
What Happens to the Current Transaction If the Session Is Killed in MySQL? If a session is killed by the DBA, the current transaction in that session will be rolled back and ended. All the database changes made in the current transaction will be removed. This is called an implicit rollback when sess...
2017-08-03, 769👍, 0💬

Non-Standard SQL Commands in MySQL
What Are the Non-Standard SQL Commands Supported by "mysql" in MySQL? There are many non-standard SQL commands that are supported by "mysql". Here is short list of some commonly used commands: "SHOW infoName" - Shows basic information of based on the specified information name. "SHOW infoName" - Sho...
2018-02-08, 768👍, 0💬

Difference between CHAR and NCHAR in MySQL
What Are the Differences between CHAR and NCHAR in MySQL? Both CHAR and NCHAR are fixed length string data types. But they have the following differences: CHAR's full name is CHARACTER. NCHAR's full name is NATIONAL CHARACTER. By default, CHAR uses ASCII character set. So 1 character is always store...
2018-01-19, 767👍, 0💬

Tables Using InnoDB Storage Engine in MySQL
How To Create a New Table Using the InnoDB Storage Engine in MySQL? InnoDB storage engine was developed by Innobase Oy, which is an Oracle company now. InnoDB is transaction safe, and has been used by a number of large Websites, like Slashdot.org. InnoDB is not the default storage engine. You need t...
2017-09-01, 766👍, 0💬

UPDATE with Subquery Returning No Rows in MySQL
What Happens If the UPDATE Subquery Returns No Rows in MySQL? If you use a subquery to assign new values in the SET clause in an UPDATE statement, and the subquery returns no rows for an outer row, MySQL will provide a NULL value to the SET clause. The tutorial exercise below shows you a good exampl...
2018-01-08, 763👍, 0💬

Updating Existing Rows in MySQL
How To Update Existing Rows in a Table in MySQL? Updating existing rows in a table requires to run the UPDATE statement with a WHERE clause to identify the row. The following sample script updates one row with two new values: &lt;?php include "mysql_connection.php"; $sql = "UPDATE fyi_links SET ...
2017-06-28, 761👍, 0💬

Transaction Waiting for a Data Lock in MySQL
How Long a Transaction Will Wait for a Data Lock in MySQL? If you issue a UPDATE or DELETE statement on a row that has an exclusive lock owned by another session, your statement will be blocked to wait for the other session to release the lock. But the wait will be timed out after the predefined inn...
2017-04-28, 760👍, 0💬

Creating a Test Table in MySQL Server in MySQL
How To Create a Test Table in Your MySQL Server in MySQL? If you want to create a test table in your MySQL server, you can use the "mysql" program in a command window as shown in the following tutorial: &gt;cd \mysql\bin &gt;mysql -u root Welcome to the MySQL monitor. Commands end with ; or ...
2018-06-06, 759👍, 0💬

Introduction to SQL Basics in MySQL
Where to find answers to frequently asked questions on Introduction to SQL Basics in MySQL? Here is a list of frequently asked questions and their answers compiled by FYIcenter.com DBA team on Introduction to SQL Basics in MySQL. Clear answers are provided with tutorial exercises on character and nu...
2018-04-21, 759👍, 0💬

Add a New Column to an Existing Table in MySQL
How To Add a New Column to an Existing Table in MySQL? If you have an existing table with existing data rows, and want to add a new column to that table, you can use the "ALTER TABLE ... ADD COLUMN" statement. The tutorial script below shows you a good example: mysql&gt; ALTER TABLE tip ADD COLU...
2018-03-04, 759👍, 0💬

What Is a Subquery in MySQL
What Is a Subquery in MySQL? A subquery is a SELECT statement used as part of the selection criteria of the main SELECT statement. The subquery specified in the WHERE clause will be evaluated repeated on each row of the selection base table. The output of the subquery will be used in the final evalu...
2017-09-17, 759👍, 0💬

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