General MySQL Oracle SQL Server

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Inserting a New Row into a Table in MySQL
How To Insert a New Row into a Table in MySQL? To insert a new row into a table, you should use the INSERT INTO statement with values specified for all columns as shown in the following example: mysql&gt; INSERT INTO fyi_links VALUES (101, 'dev.fyicenter.com', NULL, 0, '2006-04-30'); Query OK, 1... 2018-01-16, 3044🔥, 0💬

Evaluating Expressions with SELECT Statements in MySQL
How To Calculate Expressions with SELECT Statements in MySQL? There is no special SQL statements to calculate expressions. But you can use the "SELECT expression FROM DUAL" statement return the calculated value of an expression. "DUAL" is a dummy table in the server. The tutorial exercise below show... 2018-04-12, 3042🔥, 0💬

Using Table Alias Names in MySQL
How To Define and Use Table Alias Names in MySQL? When column names need to be prefixed with table names, you can define table alias name and use them to prefix column names as shown in the following select statement: mysql&gt; SELECT l.id, l.url, r.comment FROM fyi_links l INNER JOIN fyi_rates ... 2017-12-31, 3038🔥, 0💬

Memory Usage of the MySQL Server in MySQL
How Much Memory Does the Server Take in MySQL? If you are interested to know how much memory your MySQL server is taking, you can use Windows Task Manager to find out. Try to following this tutorial exercise: Start your MySQL server. Press Ctrl-Alt-Del and click Task Manager. The Task Manager window... 2017-12-04, 3038🔥, 0💬

Using CASE Expression in MySQL
How To Use CASE Expression in MySQL? There are 2 ways to use the CASE expression. The first way is to return one of the predefined values based on the comparison of a given value to a list of target values. The second way is to return one of the predefined values based on a list of conditions. Here ... 2018-03-24, 3036🔥, 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, 3036🔥, 0💬

SYSTEM_USER() - Synonym for USER()
What's the difference between SYSTEM_USER() and USER() functions? SYSTEM_USER() is a synonym for the USER() function. Related MySQL functions: USER() - Login Name of Current User SESSION_USER() - Synonym for USER() SYSTEM_USER() - Synonym for USER() CURRENT_USER() - Authentication Name of Current Us... 2025-01-07, 3035🔥, 0💬

Using SELECT Statements in Views in MySQL
Can SELECT Statements Be Used on Views in MySQL? Select (query) statements can be used on views in the same way as tables. The following tutorial exercise helps you creating a view and running a query statement on the view: mysql&gt; CREATE VIEW myLinks AS SELECT * FROM fyi_links WHERE url LIKE ... 2018-01-06, 3035🔥, 0💬

Drop an Existing Index in MySQL
How To Drop an Existing Index in MySQL? If you don't need an existing index any more, you should delete it with the "DROP INDEX indexName ON tableName" statement. Here is an example SQL script: mysql&gt; DROP INDEX tip_subject ON tip; Query OK, 0 rows affected (0.13 sec) Records: 0 Duplicates: 0... 2018-02-14, 3031🔥, 0💬

Use "mysql" to Run SQL Statements in MySQL
How To Use "mysql" to Run SQL Statements in MySQL? If you want to run SQL statement to your server with "mysql", you need to start "mysql" and enter your SQL statement at the "mysql" prompt. Here is a good tutorial exercise that shows you how to run two SQL statements with "mysql": &gt;cd \mysql... 2018-02-28, 3029🔥, 0💬

What Is SQL Standard in MySQL
What Is SQL Standard in MySQL? SQL, SEQUEL (Structured English Query Language), is a language for RDBMS (Relational Database Management Systems). SQL was developed by IBM Corporation. SQL became an ANSI standard, called SQL-87, in 1986. ISO made a major revision, called SQL-92, in 1992. The latest r... 2018-04-21, 3026🔥, 0💬

Concatenating Character Strings in MySQL
How To Concatenate Two Character Strings in MySQL? If you want concatenate multiple character strings into one, you need to use the CONCAT() function. Here are some good examples: SELECT CONCAT('Welcome',' to') FROM DUAL; Welcome to SELECT CONCAT('FYI','center','.com') FROM DUAL; FYIcenter.com   ⇒ E... 2018-04-07, 3022🔥, 0💬

Selecting All Columns of All Rows in MySQL
How To Select All Columns of All Rows from a Table in MySQL? The simplest query statement is the one that selects all columns of all rows from a single table: "SELECT * FROM tableName;". The (*) in the SELECT clause tells the query to return all columns. The missing WHERE clause tells the query to r... 2017-11-05, 3021🔥, 0💬

Selecting an Existing Database in MySQL
How To Select an Exiting Database in MySQL? The first thing after you have created a connection object to the MySQL server is to select the database where your tables are located, by using the mysql_select_db() function. If your MySQL server is offered by your Web hosting company, they will assign a... 2017-10-23, 3020🔥, 0💬

Experiment with Data Locks in MySQL
How To Experiment Data Locks in MySQL? If you want to have some experience with data locks, you can create two windows running two mysql transactions in two sessions. In session 1, you can run a UPDATE statement with REPEATABLE READ transaction isolation level to create an exclusive lock. Before com... 2017-04-28, 3018🔥, 0💬

What Is "mysqlshow" Command in MySQL
What Is "mysqlshow" in MySQL? "mysqlshow" is a command-line interface for end users to see information on tables and columns. Here are some sample commands supported by "mysqlshow": "mysqlshow" - Shows all the databases. "mysqlshow databaseName" - Shows all the tables in the specified database. "mys... 2018-02-28, 3010🔥, 0💬

Rollback the Current Transaction in MySQL
How To Rollback the Current Transaction in MySQL? If you have used some DML statements updated some data objects, you find a problem with those updates, and you don't want those updates to be permanently recorded in the database, you can use the ROLLBACK command. It will remove all the database chan... 2016-10-17, 3007🔥, 0💬

Rename an Existing User Account in MySQL
How To Rename an Existing User Account Name in MySQL? If you want to change the name of an existing user account, you can use the "RENAME USER oldName TO newName" command. The tutorial exercise below shows you how to do this: &gt;cd \mysql\bin &gt;mysql -u root -pretneciyf mysql mysql&gt... 2017-12-13, 3006🔥, 0💬

What Is Primary key in MySQL
What Is Primary Key in MySQL? A primary key is a single column or multiple columns defined to have unique values that can be used as row identifications.   ⇒ What Is Foreign Key in MySQL ⇐ What Is Row in MySQL ⇑ Database Basics and Terminologies in MySQL ⇑⇑ MySQL Database Tutorials 2017-07-07, 3002🔥, 0💬

Counting Groups Returned from GROUP BY in MySQL
How To Count Groups Returned with the GROUP BY Clause in MySQL? If you use the COUNT(*) function on groups returned with the GROUP BY clause, it will count the number of rows within each group, not the number of groups. If you want to count the number of groups, you can put the GROUP BY query into a... 2017-12-21, 2999🔥, 0💬

Delete an Existing Column in a Table in MySQL
How To Delete an Existing Column in a Table in MySQL? If you have an existing column in a table and you do not need that column any more, you can delete it with "ALTER TABLE ... DROP COLUMN" statement. Here is a tutorial script to delete an existing column: mysql&gt; ALTER TABLE tip DROP COLUMN ... 2018-03-04, 2997🔥, 0💬

Apply Filtering Criteria at Group Level in MySQL
How To Apply Filtering Criteria at Group Level in MySQL? If you want to return only specific groups from the query, you can apply filtering criteria at the group level by using the HAVING clause inside the GROUP BY clause. Note group functions can also be used in HAVING conditions. The following tut... 2017-10-16, 2997🔥, 0💬

Query with a Right Outer Join in MySQL
How To Write a Query with a Right Outer Join in MySQL? If you want to query from two tables with a right outer join, you can use the RIGHT OUTER JOIN ... ON clause in the FROM clause. The following query returns output with a right outer join from two tables: fyi_links and fyi_rates. The join condit... 2017-09-28, 2996🔥, 0💬

What Is Row in MySQL
What Is Row in MySQL? A row is a unit of data with related data items stored as one item in one column in a table.   ⇒ What Is Primary key in MySQL ⇐ What Is Column in MySQL ⇑ Database Basics and Terminologies in MySQL ⇑⇑ MySQL Database Tutorials 2017-07-15, 2996🔥, 0💬

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General MySQL Oracle SQL Server