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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.   ⇒Database Basics and Terminologies in MySQL ⇒⇒MySQL Database Tutorials
2017-07-07, 204👍, 0💬

What Is Union in MySQL
What Is Union in MySQL? Join is data retrieval operation that combines multiple query outputs of the same structure into a single output.   ⇒Database Basics and Terminologies in MySQL ⇒⇒MySQL Database Tutorials
2017-07-07, 204👍, 0💬

What Is a Table in SQL Server
What is a table in SQL Server? A table in database is a data object used to store data. Tables have the following features: Data is stored in a table with a structure of rows and columns. Columns must be pre-defined with names, types and constrains. A table object may have other associated data obje...
2016-11-20, 204👍, 0💬

Using SELECT Statements with Joins and Subqueries in SQL Server
Where to find answers to frequently asked questions on Using SELECT Statements with Joins and Subqueries in SQL Server? Here is a list of frequently asked questions and their answers compiled by FYIcenter.com DBA team on Using SELECT Statements with Joins and Subqueries in SQL Server. Clear answers ...
2016-10-30, 204👍, 0💬

"TOP" - Return the Top 5 Rows from a SELECT Query in SQL Server
How To Return the Top 5 Rows from a SELECT Query in SQL Server? If you want the query to return only the first 5 rows, you can use the "TOP 5" clause. The TOP clause takes one parameter to indicate how many top rows to return. The following statements returns the first 5 rows and 3 rows from the fyi...
2016-10-29, 204👍, 0💬

Sorting Query Output with ORDER BY Clauses in SQL Server
How To Sort the Query Output with ORDER BY Clauses in SQL Server? If you want the returning rows to be sorted, you can specify a sorting expression in the ORDER BY clause. The simplest sort expression is column name who's values will be sorted by. The following select statement returns rows sorted b...
2016-10-26, 204👍, 0💬

Creating a Logon Trigger in Express Edition in SQL Server
Can You Create a Logon Trigger in SQL Server 2005 Express Edition in SQL Server? Can you create a logon trigger in SQL Server 2005 Express Edition? The answer is no. LOGON is not a supported event type in Express Edition. The script below shows you the error message when you try to create a logon tr...
2016-10-22, 204👍, 0💬

What Is View in MySQL
What Is View in MySQL? A view is a logical table defined by a query statement.   ⇒Database Basics and Terminologies in MySQL ⇒⇒MySQL Database Tutorials
2017-07-07, 203👍, 0💬

"SELECT" Statements - Reading the Data In a Table in SQL Server
How to read data in a table with "SELECT" statements in SQL Server? This is the fourth tutorial of a quick lesson on creating database objects with Transact-SQL statements. This lesson shows you how to create a database, create a table in the database, and then access and change the data in the tabl...
2016-12-02, 203👍, 0💬

Primary Key - Default Indexes of Tables in SQL Server
Is the PRIMARY KEY Column of a Table an Index in SQL Server? If you define a primary key on a table, an index for the primary key column will be created by default. The tutorial exercise below shows you the index created as part of the primary key column of "fyi_links": USE FyiCenterData; GO -- Drop...
2016-11-13, 203👍, 0💬

Deleting an Existing Row with DELETE Statements in SQL Server
How To Delete an Existing Row with DELETE Statements in SQL Server? If you want to delete an existing row from a table, you can use the DELETE statement with a WHERE clause to identify that row. Here is good sample of DELETE statements: -- insert a row for this test INSERT INTO fyi_links (url, id) V...
2016-10-30, 203👍, 0💬

What Is a SELECT Query Statement in SQL Server
What Is a SELECT Query Statement in SQL Server? The SELECT statement is also called the query statement. It is the most frequently used SQL statement in any database application. SELECT statements allows you to retrieve data from one or more tables or views, with different selection criteria, groupi...
2016-10-26, 203👍, 0💬

Using Multiple Columns in the GROUP BY Clause in SQL Server
Can Multiple Columns Be Used in GROUP BY in SQL Server? If you want to break your output into smaller groups, you can 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 mo...
2016-10-25, 203👍, 0💬

"ALTER LOGIN" - Disabling a Login Name in SQL Server
How To Disable a Login Name in SQL Server? If you want temporarily disable a login name, you can use the "ALTER LOGIN" statement with a DISABLE keyword. If you want to enable it later on, you can use the ENABLE keyword. The tutorial exercise below shows how to disable and enable login name "Dba_Logi...
2016-10-19, 203👍, 0💬

Start a New Transaction Explicitly in MySQL
How To Start a New Transaction Explicitly in MySQL? If you are confused on the implicit new transaction rules, you can always start a new transaction with the "START TRANSACTION" command to start a new transaction explicitly. "START TRANSACTION" command works in both "Autocommit On" and "Autocommit ...
2016-10-17, 203👍, 0💬

Deleting Existing Rows in MySQL
How To Delete Existing Rows in a Table in MySQL? If you want to remove a row from a table, you can use the DELETE statement with a WHERE clause to identify the row. The following sample script deletes one row: <?php include "mysql_connection.php"; $sql = "DELETE FROM fyi_links WHERE id = 1102"; i...
2017-06-28, 202👍, 0💬

"LEFT OUTER JOIN ... ON" - Writing Queries with Left Outer Joins in SQL Server
How To Write a Query with a Left Outer Join in SQL Server? If you want to query from two tables with a left outer join, you can use the LEFT OUTER JOIN ... ON clause in the FROM clause. The following query returns output with a left outer join from two tables: fyi_links and fyi_rates. The join condi...
2016-10-30, 202👍, 0💬

Using Subqueries with the EXISTS Operators in SQL Server
How To Use Subqueries with the EXISTS Operators in SQL Server? A subquery can be used with the EXISTS operator as "EXISTS (subquery)", which returns true if the subquery returns one or more rows. The following statement is a good example of "EXISTS (subquery)". It returns rows from fyi_links table t...
2016-10-29, 202👍, 0💬

Basic Features of a Trigger in SQL Server
What Are the Basic Features of a Trigger in SQL Server? Since a SQL Server trigger is a really an event handler, it has the following basic features similar to event handlers in other programming languages: Event Type - It must be declared to handle a specific event, like a DELETE event. Object Scop...
2016-10-25, 202👍, 0💬

"ALTER AUTHORIZATION" - Changing the Ownership of a Schema in SQL Server
How To Change the Ownership of a Schema in SQL Server? If you want to change the owner of a schema, you can use the "ALTER AUTHORIZATION" statement using the following syntax: ALTER AUTHORIZATION ON SCHEMA::schema_name TO user_name The following tutorial example shows you how to change ownership of ...
2016-10-22, 202👍, 0💬

What Is CSV in MySQL
What Is CSV in MySQL? CSV (Comma Separated Values) is a file format used to store database table contents, where one table row is stored as one line in the file, and each data field is separated with comma.   ⇒Database Basics and Terminologies in MySQL ⇒⇒MySQL Database Tutorials
2016-10-16, 202👍, 0💬

"INNER JOIN ... ON" - Writing Queries with Inner Joins in SQL Server
How To Write a Query with an Inner Join in SQL Server? If you want to query from two tables with an inner join, you can use the INNER JOIN ... ON clause in the FROM clause. The tutorial exercise below creates another testing table and returns output with an inner join from two tables: fyi_links and ...
2016-10-30, 201👍, 0💬

What Is a Subquery in a SELECT Query Statement in SQL Server
What Is a Subquery in a SELECT Query Statement in SQL Server? 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 subquer...
2016-10-29, 201👍, 0💬

Creating and Managing Schemas in SQL Server
Where to find answers to frequently asked questions on Creating and Managing Schemas in SQL Server? Here is a list of frequently asked questions and their answers compiled by FYIcenter.com DBA team on Creating and Managing Schemas in SQL Server. Clear answers are provided with tutorial exercises on ...
2016-10-22, 201👍, 0💬

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