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Testing DML Triggers in SQL Server
How To Test a DML Trigger in SQL Server? To test a DML trigger defined on a table, you just need to execute several INSERT, UPDATE and DELETE statements on that table as shown in this tutorial example: USE FyiCenterData; GO INSERT INTO fyi_users (name) VALUES ('FYI Admin'); GO Records are inserted, ...
2016-10-25, 522👍, 0💬

UPDATE Using Data from Other Tables in MySQL
How To Use Values from Other Tables in UPDATE Statements in MySQL? 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 clau...
2018-01-13, 521👍, 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, 521👍, 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, 520👍, 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, 520👍, 0💬

Database in Use When Dropping a Database in SQL Server
Why I am getting this error when dropping a database in SQL Server? If you are trying to drop a database that is in use, you will get an error message like this: 'Cannot drop database "FyiCenterData" because it is currently in use.' Before dropping a database, you must stop all client sessions using...
2016-11-24, 520👍, 0💬

Creating a Simple Table to Test Triggers in SQL Server
How To Create a Simple Table to Test Triggers in SQL Server? If you want to follow other tutorial examples included in this collection, you need to run this SQL script to create a simple table called fyi_users: USE FyiCenterData; GO DROP TABLE fyi_users; GO CREATE TABLE fyi_users ( id INTEGER IDENTI...
2016-10-25, 520👍, 0💬

ONLINE/OFFLINE - Database States in SQL Server
What are database states in SQL Server? A database is always in one specific state. For example, these states include ONLINE, OFFLINE, or SUSPECT. To verify the current state of a database, select the state_desc column in the sys.databases catalog view. The following table defines the database state...
2016-11-20, 519👍, 0💬

"CREATE DATABASE" Statement - Creating New Databases in SQL Server
How to create new databases with "CREATE DATABASE" statements in SQL Server? This is the first 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 ...
2016-12-02, 516👍, 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, 516👍, 0💬

Triggers with Multiple Affected Rows in SQL Server
What Happens to a Trigger with Multiple Affected Rows in SQL Server? If there is only one row affected by a DML statement, we know that the DML trigger will be executed once. But how many times the DML trigger will be executed if the DML statement resulted multiple affected rows? The answer is still...
2016-10-24, 516👍, 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, 514👍, 0💬

Counting Groups Returned with the GROUP BY Clause in SQL Server
How To Count Groups Returned with the GROUP BY Clause in SQL Server? 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 i...
2016-10-29, 514👍, 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, 514👍, 0💬

Retrieve the Count of Updated Rows in Oracle
How To Retrieve the Count of Updated Rows in Oracle? After running an UPDATE statement, the database server returns a count of updated rows. You can retrieve this count from a special predefined variable called SQL%ROWCOUT, as shown in the following tutorial: CREATE TABLE emp_temp AS SELECT * FROM e...
2018-09-13, 513👍, 0💬

Entering Boolean Values in MySQL
How To Enter Boolean Values in SQL Statements in MySQL? If you want to enter Boolean values in SQL statements, you use (TRUE), (FALSE), (true), or (false). Here are some good examples: SELECT TRUE, true, FALSE, false FROM DUAL; +------+------+-------+------- +| TRUE | TRUE | FALSE | FALSE | +------+...
2018-03-31, 512👍, 0💬

Types of Table Joins in MySQL
How To Join Two Tables in a Single Query in MySQL? Two tables can be joined together in a query in 4 ways: Inner Join: Returns only rows from both tables that satisfy the join condition. Left Outer Join: Returns rows from both tables that satisfy the join condition, and the rest of rows from the fir...
2017-12-31, 511👍, 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, 511👍, 0💬

Create a Test Table with Test Data in MySQL
How To Create a Testing Table with Test Data in MySQL? 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: mysql&gt; CREATE TABLE fyi_links (id INTEGER PRIMARY KEY, url V...
2017-11-05, 510👍, 0💬

"INSERT" and "UPDATE" Statements - Inserting and Updating Data In Tables in SQL Server
How to insert and update data into a table with "INSERT" and "UPDATE" statements in SQL Server? This is the third 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 ...
2016-12-02, 510👍, 0💬

Joining Two Tables in a Single Query in SQL Server
How To Join Two Tables in a Single Query in SQL Server? Two tables can be joined together in a query in 4 ways: Inner Join: Returns only rows from both tables that satisfy the join condition. Left Outer Join: Returns rows from both tables that satisfy the join condition, and the rest of rows from th...
2016-10-30, 510👍, 0💬

Filtering Out Duplications in the Returning Rows in SQL Server
How To Filter Out Duplications in the Returning Rows in SQL Server? If there are duplications in the returning rows, and you want to remove the duplications, you can use the keyword DISTINCT in the SELECT clause. The DISTINCT applies to the combination of all data fields specified in the SELECT clau...
2016-10-26, 510👍, 0💬

Types of Execution Flow Control Statements in Oracle
What Are the Execution Control Statements in Oracle? PL/SQL supports three groups of execution control statements: IF Statements - Conditionally executes a block of statements. CASE Statements - Selectively executes a block of statements. LOOP Statements - Repeatedly executes a block of statements. ...
2018-11-17, 509👍, 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, 509👍, 0💬

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