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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, 355👍, 0💬

Sorting Query Output in Descending Order in SQL Server
How To Sort Query Output in Descending Order in SQL Server? If you want to sort a column in descending order, you can specify the DESC keyword in the ORDER BY clause. The following SELECT statement first sorts the "tag" in descending order, then sorts the "counts" in ascending order: SELECT tag, cou...
2016-10-26, 355👍, 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, 354👍, 0💬

Create Tables for ODBC Connection Testing in Oracle
How To Create Tables for ODBC Connection Testing in Oracle? If you want to follow the tutorial exercises in the sections below, you need to create a user account and a table for ODBC connection testing as shown here: SQL&gt; CONNECT system/retneciyf Connected. SQL&gt; CREATE USER fyi IDENTIF...
2016-10-15, 354👍, 0💬

Testing Table for SELECT Statements in SQL Server
How To Create a Testing Table with Test Data to try with SELECT statements in SQL Server? If you want to follow the tutorial exercises presented in this collection, you need to create a testing table and insert some test data, as shown in the following sample script: CREATE TABLE fyi_links (id INTEG...
2016-10-26, 353👍, 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, 352👍, 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, 350👍, 0💬

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, 350👍, 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, 350👍, 0💬

Connect ASP Pages to Oracle Servers in Oracle
How To Connect ASP Pages to Oracle Servers in Oracle? If you are running Windows IIS Web server and serving ASP Web pages, you can get data from Oracle servers into your ASP pages through ODBC drivers. To do this, you need to install the correct Oracle ODBC driver and define a DSN on the IIS Web ser...
2016-10-15, 350👍, 0💬

"mysqld" Command Line Options in MySQL
What Are the "mysqld" Command Line Options in MySQL? "mysqld" offers a big list of command line options. Here are some commonly used options: "--help" - Displays a short help message on how to use "mysqld". "--verbose --help" - Displays a long help messages on how to use "mysqld". "--console" - Spec...
2017-12-04, 349👍, 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, 349👍, 0💬

What Are DML Statements in MySQL
What Are DML Statements in MySQL? DML (Data Manipulation Language) statements are statements to change data values in database tables. The are 3 primary DML statements: INSERT - Inserting new rows into database tables. UPDATE - Updating existing rows in database tables . DELETE - Deleting existing r...
2018-01-24, 348👍, 0💬

Writing Date and Time Literals in MySQL
How To Write Date and Time Literals in MySQL? MySQL offers a number of formats for you to use to enter date and time literals: ANSI standard format: "YYYY-MM-DD HH:MM:SS". Non-standard limiters. Like: "YYYY/MM/DD HH^MM^SS" or "YYYY.MM.DD HH-MM-SS". No limiters. Like: "YYYYMMDD" for a date or "HHMMSS...
2017-12-26, 348👍, 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, 348👍, 0💬

Deleting Multiple Rows with One DELETE Statement in SQL Server
How To Delete Multiple Rows with One DELETE Statement in SQL Server? You can delete multiple rows from a table in the same way as deleting a single row, except that the WHERE clause will match multiple rows. The tutorial exercise below deletes 3 rows from the fyi_links table: -- view rows to be dele...
2016-10-30, 348👍, 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, 348👍, 0💬

Open and Close an Explicit Cursor in Oracle
How To Open and Close an Explicit Cursor in Oracle? An existing cursor can be opened or closed by the OPEN or CLOSE statement as shown in the following sample script: DECLARE CURSOR c_list IS SELECT * FROM countries; CURSOR t_list IS SELECT * FROM employees WHERE employee_id = 100; BEGIN OPEN c_list...
2018-07-22, 345👍, 0💬

Downloading and Installing MySQL on Windows
Where to find answers to frequently asked questions on Downloading and Installing MySQL on Windows? I want to learn how to install MySQL database. Here is a list of frequently asked questions and their answers compiled by FYIcenter.com DBA team on Downloading and Installing MySQL on Windows. Clear a...
2018-06-12, 345👍, 0💬

Categories of Functions Based on Return Modes in SQL Server
How Many Categories of Functions based Their Return Modes in SQL Server Transact-SQL? SQL Server supports 2 categories of user defined functions based on their return modes: 1. Scalar-valued Functions - A function that returns a single value. Scalar-valued functions can be used in scalar expressions...
2016-12-18, 345👍, 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, 345👍, 0💬

Using Group Functions in the SELECT Clause in SQL Server
How To Use Group Functions in the SELECT Clause in SQL Server? If group functions are used in the SELECT clause, all rows that meet the criteria defined in the WHERE clause will be treated as a single group. The group functions will be apply all rows in that group as a whole. The final output of the...
2016-10-25, 345👍, 0💬

"GROUP BY" - Dividing Query Output into Multiple Groups in SQL Server
How To Divide Query Output into Multiple Groups with the GROUP BY Clause in SQL Server? Sometimes, you want to divide the query output into multiple groups, and apply group functions on each individual groups. Dividing query output into multiple groups can be done with the GROUP BY clause. Here is t...
2016-10-25, 345👍, 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, 344👍, 0💬

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