General MySQL Oracle SQL Server

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JSON_VALID() - Validating JSON Value
How to verify if value is a JSON (JavaScript Object Notation) value using the JSON_VALID() function? JSON_VALID(val) is a MySQL built-in function that returns 1 if the given value is a valid JSON value. For example: SELECT JSON_VALID('hello'), JSON_VALID('"hello"'); -- +---------------------+------- ... 2023-12-17, 2838🔥, 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, 2835🔥, 0💬

What Is Column in MySQL
What Is Column in MySQL? A column defines one piece of data stored in all rows of the table.   ⇒ What Is Row in MySQL ⇐ What Is Table in MySQL ⇑ Database Basics and Terminologies in MySQL ⇑⇑ MySQL Database Tutorials 2017-07-15, 2833🔥, 0💬

Using Multiple Columns in GROUP BY in MySQL
Can Multiple Columns Be Used in GROUP BY in MySQL? If you want to break your output into smaller groups, if you specify multiple column names or expressions in the GROUP BY clause. Output in each group must satisfy a specific combination of the expressions listed in the GROUP BY clause. The more col... 2017-10-16, 2832🔥, 0💬

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, 2819🔥, 0💬

What Is "mysqldump" Command in MySQL
What Is "mysqldump" in MySQL? "mysqldump" - A command-line interface for administrators or end users to export data from the server to files. Here are some sample commands supported by "mysqldump": "mysqldump databaseName tableName" - Dumps the specified table in the specified database. "mysqldump d... 2018-05-19, 2808🔥, 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, 2807🔥, 0💬

Starting mysqld to Support BDB Storage Engine in MySQL
How To Start mysqld to Support the BDB Storage Engine in MySQL? The default "mysqld" program does not support the BDB storage engine. If you want to use the BDB storage engine, you can start MySQL server with the "mysqld-max" program. The tutorial exercise below shows you how to start "mysqld-max" a... 2017-08-13, 2804🔥, 0💬

Tables Using MyISAM Storage Engine in MySQL
How To Create a New Table Using MyISAM Storage Engine in MySQL? MyISAM storage engine is based on the ISAM (Indexed Sequential Access Method) concept, which was first developed at IBM to store and retrieve data on secondary storage systems like tapes. MyISAM storage engine offers fast data storage a... 2017-09-12, 2802🔥, 0💬

Key Word Search in Tables in MySQL
How To Perform Key Word Search in Tables in MySQL? The simplest way to perform key word search is to use the SELECT statement with a LIKE operator in the WHERE clause. The LIKE operator allows you to match a text field with a keyword pattern specified as '%keyword%', where (%) represents any number ... 2017-06-23, 2801🔥, 0💬

Loading Data Files with "mysqlimport" Command in MySQL
How To Load Data Files into Tables with "mysqlimport" in MySQL? If you want to load a data file directly into a table, you need to prepare the data file as one line per data row, and use tab character as the column delimiter. The data file name should match the target table name. The following is a ... 2018-04-28, 2798🔥, 0💬

Using Column Default Values in MySQL
How To Specify Default Values in INSERT Statement in MySQL? If a column is defined with a default value in a table, you can use the key word DEFAULT in the INSERT statement to take the default value for that column. The following tutorial exercise gives a good example: mysql&gt; INSERT INTO fyi_... 2018-01-16, 2795🔥, 0💬

Shutting Down MySQL Server in MySQL
How To Shutdown MySQL Server in MySQL? If you want to shutdown your MySQL server, you can run the "mysqladmin" program in a command window as shown in the following tutorial: &gt;cd \mysql\bin &gt;mysqladmin shutdown   ⇒ Administrator Tools for Managing MySQL Server ⇐ Creating a Test Table ... 2018-06-06, 2789🔥, 0💬

Read Consistency Support in MySQL in MySQL
How Does MySQL Handle Read Consistency in MySQL? Read consistency is a concept that describes how consistent the output will be on two subsequent read operations. A read operation is usually a stand alone SELECT statement or a SELECT subquery in a parent statement. A database server can support up t... 2017-08-03, 2789🔥, 0💬

Select Rows with WHERE Clause in MySQL
How To Select Some Rows from a Table in MySQL? If you don't want select all rows from a table, you can specify a WHERE clause to tell the query to return only the rows that meets the condition defined in the WHERE clause. The WHERE clause condition is a normal Boolean expression. If any data from ta... 2017-11-02, 2788🔥, 0💬

VERSION() - Version Number of MySQL Server
How to obtain the version number of the MySQL server using the VERSION() function? VERSION() is a MySQL built-in function that returns the version number of the MySQL server. For example: SELECT VERSION(); -- +-----------+ -- | VERSION() | -- +-----------+ -- | 8.0.17 | -- +-----------+ SELECT @@ver... 2025-01-07, 2783🔥, 0💬

DDL Commands Supported in MySQL
How Many SQL DDL Commands Are Supported by "mysql" in MySQL? There are 4 SQL Data Definition Language (DDL) commands that are supported by "mysql". They are listed below with short descriptions: "CREATE dataObjectType dataObjectName" - Creates new databases, tables, views, triggers, indexes, and oth... 2018-04-21, 2782🔥, 0💬

Order of Columns in the SET Clause in MySQL
Is the Order of Columns in the SET Clause Important in MySQL? Yes. The order of columns in the SET clause of the UPDATE statement is important. There is a BIG DIFFERENCE between MySQL and Oracle on update columns with previous values: Oracle provides you the existing values from the database on colu... 2018-01-13, 2782🔥, 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, 2782🔥, 0💬

Data File for InnoDB Storage Engine in MySQL
Where Table Data Is Stored by the InnoDB Storage Engine in MySQL? By default, MySQL provides \mysql\data directory for all storage engines to store table data. Under \mysql\data directory, InnoDB storage engine will create 3 files to store and manage all tables that use the InnoDB storage engine: ib... 2017-08-13, 2774🔥, 0💬

Entering Binary Numbers in MySQL
How To Enter Binary Numbers in SQL Statements in MySQL? If you want to enter character strings or numeric values as binary numbers, you can quote binary numbers with single quotes and a prefix of (B), or just prefix binary numbers with (0b). Binary numbers will be automatically converted into charac... 2018-03-31, 2773🔥, 0💬

Use Existing Column Values in the SET Clause in MySQL
How To Use Existing Column Values in the SET Clause in MySQL? If a row matches the WHERE clause in a UPDATE statement, existing values in this row can be used in expressions to provide new values in the SET clause. Existing values are represented by column names in the expressions. The tutorial exer... 2018-01-13, 2770🔥, 0💬

List Table Names with "mysqlshow" Command in MySQL
How To Show Table Names with "mysqlshow" in MySQL? If you want to show table names with "mysqlshow", you need to specify a database name. The followings tutorial exercise shows you how to get all table names that match a pattern: If you want analyze tables with "mysqlcheck", you need to use the "--a... 2018-05-19, 2765🔥, 0💬

What are Date and Time Data Types in MySQL
What Are Date and Time Data Types in MySQL? MySQL supports the following date and time data types: DATE - A date in the range of '1000-01-01' and '9999-12-31'. Default DATE format is "YYYY-MM-DD". DATETIME - A date with the time of day in the range of '1000-01-01 00:00:00' and '9999-12-31 23:59:59'.... 2018-03-24, 2764🔥, 0💬

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General MySQL Oracle SQL Server