<< < 25 26 27 28 29 30 31 >   Sort: Date

Creating a Large Table with Random Data for Indexes in SQL Server
How To Create a Large Table with Random Data for Index Testing in SQL Server? If you want to see how index can be used to improve data search performance, you have to build some large tables, which requires large amount of random data. This tutorial exercise helps you to build a large table with pur...
2016-11-13, 324👍, 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, 323👍, 0💬

Returning Query Output in XML Format in MySQL
How To Return Query Output in XML Format in MySQL? By default, "mysql" returns query output in text table format. If you want to receive query output in XML format, you need to use the "-X" command option. Here is a good tutorial exercise: &gt;cd \mysql\bin &gt;mysql -u root -X test mysql&am...
2018-04-21, 321👍, 0💬

What Is "mysqldump" Command in MySQL
What Is "mysqldump" in MySQL? "mysqldump" - A command-line interface for administrators or end users to export data from the server to files. Here are some sample commands supported by "mysqldump": "mysqldump databaseName tableName" - Dumps the specified table in the specified database. "mysqldump d...
2018-05-19, 320👍, 0💬

Start an Oracle Instance in Oracle
How To Start an Oracle Instance in Oracle? This is Step 6. Now you are ready to start the new Oracle Instance without any database. This instance will be used to create a database. Starting an instance without database can be done by using STARTUP NOMOUNT statement as shown below: &gt;.\bin\sqlp...
2018-05-08, 320👍, 0💬

Groups of Data Types in MySQL
How Many Groups of Data Types in MySQL? MySQL support 3 groups of data types as listed below: String Data Types - CHAR, NCHAR, VARCHAR, NVARCHAR, BINARY, VARBINARY, TINYBLOB, TINYTEXT, BLOB, TEXT, MEDIUMBLOB, MEDIUMTEXT, LONGBLOB, LONGTEXT, ENUM, SET Numeric Data Types - BIT, TINYINT, BOOLEAN, SMALL...
2018-04-21, 320👍, 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, 320👍, 0💬

Getting a List of All Databases on the Server in SQL Server
How to get a list all databases on the SQL server in SQL Server? If you don't remember database names you have created, you can get a list of all databases on the server by query the "sys.databases" view as shown in this tutorial example: CREATE DATABASE FyiCenterData GO SELECT name, database_id, cr...
2016-11-24, 320👍, 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, 320👍, 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, 319👍, 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, 318👍, 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, 317👍, 0💬

Insert Multiple Rows with 1 INSERT Statement in MySQL
How To Insert Multiple Rows with One INSERT Statement in MySQL? If you want to insert multiple rows with a single INSERT statement, you can use a subquery instead of the VALUES clause. Rows returned from the subquery will be inserted the target table. The following tutorial exercise gives a good exa...
2018-01-16, 316👍, 0💬

Incrementing a Date by 1 in MySQL
How To Increment Dates by 1 in MySQL? If you have a date, and you want to increment it by 1 day, you can use the DATE_ADD(date, INTERVAL 1 DAY) function. You can also use the date interval add operation as "date + INTERVAL 1 DAY". The tutorial exercise below gives you some good examples: SELECT DATE...
2017-12-26, 316👍, 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, 316👍, 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, 314👍, 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, 313👍, 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, 313👍, 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, 313👍, 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, 313👍, 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, 312👍, 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, 312👍, 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, 312👍, 0💬

Run CREATE DATABASE Statement in Oracle
How To Run CREATE DATABASE Statement in Oracle? This is Step 7. Oracle Administrator Guide provided a sample CREATE DATABASE statement. But it is a long statement. You can modify and same it in a file, $ORACLE_HOME/configscripts/cre ate_database_fyi.sql,and run the file within SQL*Plus. Here is a co...
2018-05-08, 311👍, 0💬

<< < 25 26 27 28 29 30 31 >   Sort: Date