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Select Some Columns from a Table in Oracle
How To Select Some Columns from a Table in Oracle? If you want explicitly tell the query to some columns, you can specify the column names in SELECT clause. The following select statement returns only two columns from the table "departments": SQL&gt; SELECT location_id, department_name FROM DEPA...
2019-12-19, 636👍, 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, 636👍, 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, 636👍, 0💬

Predefined User Accounts in MySQL
What Are the Predefined User Accounts in MySQL? There is only one predefined user account called "root": "root" was created during the installation process. "root" has no password initially. You need to assign a new password as soon as you finishes the installation. "root" has all access privileges ...
2017-09-08, 636👍, 0💬

Using ORDER BY with UNION Operators in SQL Server
How To Use ORDER BY with UNION Operators in SQL Server? If you need to sort the output from two queries grouped together with a UNION operator, you need to apply the ORDER BY clause at the group level, not at the subquery level. Note that SQL Server and MySQL react differently to the ORDER BY clause...
2016-10-26, 636👍, 0💬

Transaction Committed when START TRANSACTION Executed in MySQL
What Happens to the Current Transaction If a START TRANSACTION Is Executed in MySQL? If you are in a middle of a current transaction, and a START TRANSACTION command is executed, the current transaction will be committed and ended. All the database changes made in the current transaction will become...
2016-10-17, 636👍, 0💬

Use Subqueries in the FROM Clause in Oracle
How To Use Subqueries in the FROM Clause in Oracle? If you have a query returning many rows of data, and you want to perform another query on those rows, you can put the first query as a subquery in the FROM clause of the second query. The following statement shows you how to use a subquery as base ...
2019-09-27, 635👍, 0💬

Connecting to MySQL Server on a Specific Port in MySQL
How To Connect to MySQL Server on a Different Port in MySQL? If your MySQL server is listening on port number different than 3306, you need to specify "--port=portNumber" option to any client program that needs to connect to the server. The tutorial exercise shows you how to connect "mysql" to start...
2017-11-25, 635👍, 0💬

Creating a View with Data from Another View in SQL Server
Can You Create a View using Data from Another View in SQL Server? Can You Create a View with Data from Another View? The answer is yes. A view can be used as a table to build other views. The tutorial exercise below shows you how to create a view using data from another view: USE AdventureWorksLT; G...
2016-11-05, 635👍, 0💬

Commit the Current Transaction in MySQL
How To Commit the Current Transaction in MySQL? If you have used some DML statements updated some data objects, and you want to have the updates to be permanently recorded in the database, you can use the COMMIT command. It will make all the database changes made in the current transaction become pe...
2016-10-17, 635👍, 0💬

Differences between NUMBER and BINARY_FLOAT in Oracle
What Are the Differences between NUMBER and BINARY_FLOAT in Oracle? The main differences between NUMBER and BINARY_FLOAT are: NUMBER stores values as fixed-point numbers using 1 to 22 bytes. BINARY_FLOAT stores values as single precision floating-point numbers.   ⇒Understanding SQL Language Basics f...
2020-04-25, 634👍, 0💬

Use Values from Other Tables in UPDATE in Oracle
How To Use Values from Other Tables in UPDATE Statements in Oracle? If you want to update values in one with values from another table, you can use a subquery in the SET clause. The subquery should return only one row for each row in the update table that matches the WHERE clause. The tutorial exerc...
2020-01-21, 634👍, 0💬

Delete a User Account in Oracle
How To Delete a User Account in Oracle? If you want to delete a user account and its associated schema, you can log in as SYSTEM and use the DROP USER command as shown in the following example: &gt;.\bin\sqlplus /nolog SQL&gt; connect SYSTEM/fyicenter Connected. SQL&gt; DROP USER DEV CAS...
2019-07-09, 634👍, 0💬

Using Subqueries in the FROM Clause in MySQL
How To Use Subqueries in the FROM clause in MySQL? If you have a query returning many rows of data, and you want to perform another query on those rows, you can put the first query as a subquery in the FROM clause of the second query. A subquery used in this way become a temporary table, and you mus...
2017-12-21, 634👍, 0💬

Understanding and Managing Views in SQL Server
Where to find answers to frequently asked questions on Understanding and Managing Views in SQL Server? Here is a list of frequently asked questions and their answers compiled by FYIcenter.com DBA team on Understanding and Managing Views in SQL Server. Clear answers are provided with tutorial exercis...
2016-11-08, 634👍, 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, 634👍, 0💬

Filerting out Duplications in Returning Rows in MySQL
How To Filter Out Duplications in Returning Rows in MySQL? 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 clause. The t...
2018-01-06, 633👍, 0💬

Adding Address Records into AdventureWorksLT in SQL Server
How to add an address record into AdventureWorksLT in SQL Server? To find out if we can add data into AdventureWorksLT or not, you can try to add an address record into the "SalesLT.Address" in AdventureWorksLT: USE AdventureWorksLT GO INSERT SalesLT.Address (AddressLine1, City, StateProvince, Count...
2016-12-02, 633👍, 0💬

Delete an Existing Row from a Table in Oracle
How To Delete an Existing Row from a Table in Oracle? 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 INTO fyi_links (url, id) VALUES ('http://www.myspace.com', 301); 1 row...
2020-01-04, 632👍, 0💬

Ways to Start MySQL Server in MySQL
How To Start MySQL Server Daemon mysqld in MySQL? There are a number of ways to start MySQL server daemon, mysqld: Double click on the file name, mysqld.exe, in a file explorer window. This is an easy way to start the server. But you will not be able to specify any command line options. Enter "mysql...
2017-12-04, 632👍, 0💬

What Are Cursors in SQL Server
What Are Cursors in SQL Server Transact-SQL? A cursor is a special data type that represents a result set returned by a SELECT query statement. There are several notes about cursor you need to remember: Cursor data type can not be used to define table columns. Cursor data type is used on store proce...
2016-10-17, 632👍, 0💬

ANSI Data Types in Oracle
What Are the ANSI Data Types Supported in Oracle in Oracle? The following ANSI data types are supported in Oracle: CHARACTER(n) / CHAR(n) CHARACTER VARYING(n) / CHAR VARYING(n) NATIONAL CHARACTER(n) / NATIONAL CHAR(n) / NCHAR(n) NATIONAL CHARACTER VARYING(n) / NATIONAL CHAR VARYING(n) / NCHAR VARYIN...
2020-04-14, 631👍, 0💬

Define a RECORD Variable for a Table Row in Oracle
How To Define a RECORD Variable to Store a Table Row in Oracle? If you have a table, and want to define a RECORD variable to store all the data elements of a row from that table, you can use table_name%ROWTYPE to define the RECORD variable as shown in the following sample script: CREATE TABLE studen...
2018-08-14, 631👍, 0💬

What Is BDB in MySQL
What Is BDB (BerkeleyDB) in MySQL? BDB (BerkeleyDB) is transaction safe storage engine originally developed at U.C. Berkeley. It is now developed by Sleepycat Software, Inc. (an Oracle company now).   ⇒Database Basics and Terminologies in MySQL ⇒⇒MySQL Database Tutorials
2017-07-03, 631👍, 0💬

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