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What Are Triggers in SQL Server
What Are Triggers in SQL Server? A trigger is a special kind of stored procedure that automatically executes when an event occurs in the database server. A trigger is really an event handler. SQL Server allows users to create triggers (event handlers) for 3 types of events: DML Event - Occurs when a...
2016-10-25, 507👍, 0💬

Mixing Group Functions with Non-group Selection Fields in SQL Server
Can Group Functions Be Mixed with Non-group Selection Fields in SQL Server? If a group function is used in the SELECT clause, all other selection fields must be group level fields. Non-group fields can not be mixed with group fields in the SELECT clause. The script below gives you an example of inva...
2016-10-25, 506👍, 0💬

Security Model Used in SQL Server 2005 in SQL Server
What Is the Security Model Used in SQL Server 2005 in SQL Server? SQL Server 2005 uses a very standard security model involves 3 concepts: Securables - Entities representing resources that need to be secured. For example, a database table is a securable. Principals - Entities representing users that...
2016-10-20, 500👍, 0💬

UPDATE Subquery Returning No Rows in SQL Server
What Happens If the UPDATE Subquery Returns No Rows in SQL Server? 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, SQL Server will provide a NULL value to the SET clause. The tutorial exercise below shows you a g...
2016-11-02, 499👍, 0💬

Accessing a Schema Not Owned by You in SQL Server
What Happens If You Are Trying to Access a Schema Not Owned by You in SQL Server? In general, if you are trying to access an object in schema owned by another database user, you will get a "permission denied" error, unless that you have been granted access permission to that object explicitly. Here ...
2016-10-22, 499👍, 0💬

Using Subqueries with the IN Operators in SQL Server
How To Use Subqueries with the IN Operators in SQL Server? A subquery can be used with the IN operator as "expression IN (subquery)". The subquery should return a single column with one or more rows to form a list of values to be used by the IN operation. The following tutorial exercise shows you ho...
2016-10-29, 498👍, 0💬

UNION - Merging Outputs from Two Queries Together in SQL Server
How To Use UNION to Merge Outputs from Two Queries Together in SQL Server? If you have two queries that returns the same row fields, you can merge their outputs together with the UNION operator. The following tutorial exercise shows you how to use the UNION operator: SELECT * FROM fyi_links WHERE ta...
2016-10-26, 498👍, 0💬

Using User Defined Functions in Expressions in SQL Server
How To Use User Defined Functions in Expressions in SQL Server Transact-SQL? An user defined function must return a value, which can be used in any expression as long as the return value data type matches the expression. To execute a user defined function and use its return value in an expression, y...
2016-12-24, 497👍, 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, 497👍, 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, 496👍, 0💬

Group Functions in Query Statements in SQL Server
What Are Group Functions in Query Statements in SQL Server? Group functions are functions applied to a group of rows. Examples of group functions are: COUNT(*) - Returns the number of rows in the group. MIN(exp) - Returns the minimum value of the expression evaluated on each row of the group. MAX(ex...
2016-10-25, 495👍, 0💬

Ways to End the Current Transaction in MySQL
How To End the Current Transaction in MySQL? There are several ways the current transaction can be ended implicitly or explicitly: In "Autocommit On" mode, a single-statement transaction will be ended implicitly when the execution of the statement ends. Changes will be committed. Running the COMMIT ...
2016-10-17, 495👍, 0💬

Using LIKE Conditions in MySQL
How To Use LIKE Conditions in MySQL? A LIKE condition is also called pattern patch. There are 3 main rules on using LIKE condition: '_' is used in the pattern to match any one character. '%' is used in the pattern to match any zero or more characters. ESCAPE clause is used to provide the escape char...
2018-03-24, 494👍, 0💬

Using Values from Other Tables in UPDATE Statements in SQL Server
How To Use Values from Other Tables in UPDATE Statements in SQL Server? If you want to update values in one table with values from another table, you can use a subquery as an expression in the SET clause. The subquery should return only one row for each row in the update table that matches the WHERE...
2016-11-02, 494👍, 0💬

Error: Single-Row Subquery Returns More Than One Row in Oracle
What Happens If the UPDATE Subquery Returns Multiple Rows in Oracle? If a subquery is used in a UPDATE statement, it must return exactly one row for each row in the update table that matches the WHERE clause. If it returns multiple rows, Oracle server will give you an error message. To test this out...
2020-01-21, 493👍, 0💬

System Requirements for SQL Server 2005 Express Edition in SQL Server
What are the requirements to install SQL Server 2005 Express Edition in SQL Server? The following system requirements cover the SQL Server 2005 Express Edition: Processor 32-bit Processor of 600-megahertz (MHz) or faster Operating System Windows XP with Service Pack 2 or later Windows 2000 Professio...
2016-12-08, 486👍, 0💬

Selecting Columns in a Query in MySQL
How To Select Some Columns from a Table in MySQL? If you want explicitly tell the query to return some columns, you can specify the column names in the SELECT clause. The following select statement returns only two columns, "id" and "url" from the table "fyi_links": mysql&gt; SELECT id, url FROM...
2017-11-05, 485👍, 0💬

Using Old Values to Define New Values in UPDATE Statements in SQL Server
How to use old values to define new values in UPDATE statements in SQL Server? 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. ...
2016-11-02, 482👍, 0💬

"CREATE SCHEMA" - Creating a New Schema in a Database in SQL Server
How To Create a New Schema in a Database in SQL Server? If you want to create a new schema in an existing database, you can use the "CREATE SCHEMA" statement as shown in the tutorial example below: USE FyiCenterData; GO CREATE SCHEMA fyi; GO Command(s) completed successfully. A new schema called "fy...
2016-10-22, 482👍, 0💬

HAVING - Apply Filtering Criteria at Group Level in SQL Server
How To Apply Filtering Criteria at Group Level with The HAVING Clause in SQL Server? Let's say you have divided the query output into multiple groups with the GROUP BY clause. Now you are only interested in some of the groups, not all the groups. If you want to filter out some groups from the query,...
2016-10-25, 481👍, 0💬

Providing Column Names in INSERT Statements in SQL Server
How to provide column names in INSERT Statements in SQL Server? 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 is om...
2016-11-02, 471👍, 0💬

Selecting Some Specific Rows from a Table in SQL Server
How To Select Some Specific Rows from a Table in SQL Server? 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 an...
2016-10-26, 469👍, 0💬

Simplest Way To Create New Databases in SQL Server
What is the simplest way to create a new database in SQL Server? The simplest way to create a new database is to use the "CREATE DATABASE" statement with this syntax: CREATE DATABASE database_name For example, run this statement: CREATE DATABASE FyiCenterData GO A new database called "FyiCenterData"...
2016-11-24, 462👍, 0💬

Creating an Index on a View in SQL Server
How To Create an Index on a View in SQL Server? If you need to search and sort data in a view with a large number of row, you may want to create an index on the view to speed up your search process. The tutorial exercise below shows you how to create a unique clustered index on a view. DROP VIEW fyi...
2016-11-03, 458👍, 0💬

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