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Extract Unit Values from a Date and Time in MySQL
How To Extract a Unit Value from a Date and Time in MySQL? If you want to extract a specific date or time unit value out of a date or a time, you can use the EXTRACT(unit FROM expression) function. The tutorial exercise below gives you some good examples: ELECT EXTRACT(DAY FROM NOW()) FROM DUAL; 28 ...
2018-03-13, 518👍, 0💬

What Is a RECORD in PL/SQL in Oracle
What Is a RECORD in PL/SQL in Oracle? RECORD is a composite data type in PL/SQL. It can have many fields representing data elements with different data types. Variables of RECORD type can be designed to hold data from database table rows. To use RECORD data type, you need to define a specific RECORD...
2018-09-13, 517👍, 0💬

Including Comments in SQL Statements in MySQL
How To Include Comments in SQL Statements in MySQL? If you want to include comments in a SQL statement, you can first enter "--", then enter your comment until the end of the line. The tutorial exercise below shows you some good examples: SELECT 'Hello world!' FROM DUAL; -- My first SQL statement! I...
2018-04-12, 517👍, 0💬

Entering Numeric Values as HEX Numbers in MySQL
How To Enter Numeric Values as HEX Numbers in MySQL? If you want to enter numeric values as HEX numbers, you can quote HEX numbers with single quotes and a prefix of (X), or just prefix HEX numbers with (0x). A HEX number string will be automatically converted into a numeric value, if the expression...
2018-03-31, 517👍, 0💬

Show All Tables in a Database in MySQL
How To Get a List of All Tables in a Database in MySQL? If you want to see the table you have just created, you can use the "SHOW TABLES" command to get a list of all tables in database. The tutorial script gives you a good example: mysql&gt; SHOW TABLES; +---------------+ | Tables_in_fyi | +---...
2018-03-10, 517👍, 0💬

Inserting a New Row into a Table in MySQL
How To Insert a New Row into a Table in MySQL? To insert a new row into a table, you should use the INSERT INTO statement with values specified for all columns as shown in the following example: mysql&gt; INSERT INTO fyi_links VALUES (101, 'dev.fyicenter.com', NULL, 0, '2006-04-30'); Query OK, 1...
2018-01-16, 517👍, 0💬

Query with a Full Outer Join in MySQL
How To Write a Query with a Full Outer Join in MySQL? There is no way to do full outer join in MySQL. It does not support this feature at the current MySQL release.   ⇒SELECT Statements with JOIN and Subqueries in MySQL ⇒⇒MySQL Database Tutorials
2017-09-28, 517👍, 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, 517👍, 0💬

Shutting Down MySQL Server in MySQL
How To Shutdown MySQL Server in MySQL? If you want to shutdown your MySQL server, you can run the "mysqladmin" program in a command window as shown in the following tutorial: &gt;cd \mysql\bin &gt;mysqladmin shutdown   ⇒Downloading and Installing MySQL on Windows ⇒⇒MySQL Database Tutorials
2018-06-06, 516👍, 0💬

What Are DDL Statements in MySQL
What Are DDL Statements in MySQL? DDL (Data Definition Language) statements are statements to create and manage data objects in the database. The are 3 primary DDL statements: CREATE - Creating a new database object. ALTER - Altering the definition of an existing data object. DROP - Dropping an exis...
2018-03-10, 516👍, 0💬

Returning Top 5 Rows in MySQL
How To Return Top 5 Rows in MySQL? If you want the query to return only the first 5 rows, you can use the LIMIT clause, which takes one parameter as the maximum number of rows to return. The following statement returns the first 5 rows from the fyi_links: mysql&gt; SELECT id, url, counts, tag FR...
2017-12-21, 516👍, 0💬

Creating Triggers for INSERT Statements Only in SQL Server
How To Create a Trigger for INSERT Only in SQL Server? The trigger, dml_message, provided in previous tutorials was defined to handle all 3 types of DML statements, INSERT, UPDATE, and DELETE. If you do not want the trigger to handle all 3 types of DML statements, you can list only 1 or 2 of the sta...
2016-10-24, 516👍, 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, 516👍, 0💬

Drop a Tablespace in Oracle
How To Drop a Tablespace in Oracle? If you have an existing tablespace and you don't want it anymore. You can delete a tablespace by using the DROP TABLESPACE statement as shown in the example below: SQL&gt; CREATE TABLESPACE my_space 2 DATAFILE '/temp/my_space.dbf' SIZE 10M; Tablespace created....
2019-04-13, 515👍, 0💬

Data Types Supported in PL/SQL in Oracle
How Many Data Types Are Supported in Oracle? PL/SQL supports two groups of data types: SQL Data Types - All data types used for table columns. PL/SQL Special Data Types - Like BOOLEAN or PLS_INTEGER. The script below shows some data type examples: SQL&gt; set serveroutput on; SQL&gt; DECLARE...
2019-03-20, 515👍, 0💬

Count Number of Rows with SELECT Statements in MySQL
How To Use SELECT Statement to Count Number of Rows in MySQL? If you want to count the number of rows, you can use the COUNT(*) function in the SELECT clause. The following tutorial exercise shows you some good example: mysql&gt; SELECT COUNT(*) FROM fyi_links; +----------+ | COUNT(*) | +-------...
2018-01-06, 515👍, 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, 515👍, 0💬

NULL Values Involved in Bitwise Operations in SQL Server
What Happens If NULL Values Are Involved in Bitwise Operations in SQL Server Transact-SQL? If NULL values are involved in bitwise operations, the result will be binary NULL values. The following tutorial script shows you some good examples: SELECT 1 | NULL; GO ----------- NULL SELECT 707 &amp; N...
2017-02-03, 515👍, 0💬

Difference Between Clustered and Non-Clustered Indexes in SQL Server
What Is the Difference Between Clustered and Non-Clustered Indexes in SQL Server? SQL Server 2005 supports two types of indexes: clustered index and non-clustered index. Here are the main differences between them: One table can only have only one clustered index. One table can only have many non-clu...
2016-11-13, 515👍, 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, 515👍, 0💬

"INSTEAD OF" - Overriding DML Statements with Triggers in SQL Server
How To Override DML Statements with Triggers in SQL Server? Sometime, you may want to implement some business logics in a DML trigger to cancel the DML statement. For example, you may want to check the new email address format provided by the UPDATE statement. If the email address is invalid, you to...
2016-10-22, 515👍, 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: &lt;?php include "mysql_connection.php"; $sql = "DELETE FROM fyi_links WHERE id = 1102...
2017-06-28, 514👍, 0💬

Generating CREATE PROCEDURE Scripts on Existing Stored Procedures in SQL Server
How To Generate CREATE PROCEDURE Script on an Existing Stored Procedure in SQL Server Transact-SQL? If you want to know how an existing stored procedure was created, you can use SQL Server Management Studio to automatically generate a "CREATE PROCEDURE" script The following tutorial shows you how to...
2017-01-05, 514👍, 0💬

Running CREATE DATABASE Statement Again in Oracle
How To Run CREATE DATABASE Statement Again in Oracle? After cleaning up the results of a previously failed CREATE DATABASE statement, you can run the CREATE DATABASE statement again as shown below: SQL&gt; @$ORACLE_HOME\config\scripts\c reate_database_fyi.sql;CREATE DATABASE FYI * ERROR at line ...
2019-03-27, 513👍, 0💬

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