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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, 238👍, 0💬

OFFLINE - Taking a database offline in SQL Server
How to set a database state to OFFLINE in SQL Server? If you want to move database physical files, you should take the database offline by using the "ALTER DATABASE" statement with the following syntax: ALTER DATABASE database_name SET OFFLINE The following tutorial example will bring "FyiCenterComD...
2016-11-20, 238👍, 0💬

"DELETED" - Old Record of an DML Event Instance in SQL Server
How To Access the Deleted Record of an Event in SQL Server? When a DML event occurs, SQL Server will prepare a temporary table called "DELETED", which contains the old record of the affected row, which is: A copy of the deleted row for a DELETE statement. A copy of the row to be updated for an UPDAT...
2016-10-24, 238👍, 0💬

Sorting Output in Descending Order in MySQL
How To Sort Output in Descending Order in MySQL? 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: mysql&gt; SELECT tag, ...
2017-11-02, 237👍, 0💬

"DROP TABLE" - Deleting Existing Tables in SQL Server
How To Drop an Existing Table with "DROP TABLE" Statements in SQL Server? If you want to delete an existing table and its data rows, you can use the "DROP TABLE" statement as shown in the tutorial script below: SELECT * FROM tipBackup GO id subject description create_date 1 Learn SQL Visit dev.fyice...
2016-11-15, 237👍, 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, 237👍, 0💬

Group Functions in Query Statements in SQL Server
What Are Group Functions in Query Statements in SQL Server? Group functions are functions applied to a group of rows. Examples of group functions are: COUNT(*) - Returns the number of rows in the group. MIN(exp) - Returns the minimum value of the expression evaluated on each row of the group. MAX(ex...
2016-10-25, 237👍, 0💬

"FETCH" - Fetching the Next Row from a Cursor in SQL Server
How To Fetch the Next Row from a Cursor with a "FETCH" Statement in SQL Server Transact-SQL? When the result set is ready in a cursor, you can use a FETCH statement to retrieve one row from the result set in the same format as a SELECT statement. The FETCH statement has the following formats: FETCH ...
2016-10-17, 237👍, 0💬

"OPEN" - Executing the Query of a Cursor in SQL Server
How To Execute the Cursor Queries with "OPEN" Statements in SQL Server Transact-SQL? Once a cursor is declared, you need to execute the query attached to the cursor so that the result set returned from the query can be accessed through the cursor. To execute the cursor query, you should use the OPEN...
2016-10-17, 237👍, 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, 236👍, 0💬

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, 236👍, 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, 236👍, 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, 236👍, 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, 236👍, 0💬

Failed to Create a Database in MySQL
What Happens If You Do Not Have Privileges to Create Database in MySQL? If your MySQL server is provided by your Internet service company, your user account will most likely have no privilege to create new databases on the server. In that case, your CREATE DATABASE statement will fail. Here is an ex...
2017-11-11, 235👍, 0💬

Importance of Column Order in the SET Clause in Update Statements in SQL Server
Is the Order of Columns in the SET Clause Important in SQL Server? The answer is NO. The order of columns in the SET clause of the UPDATE statement is NOT important. You probably already noticed from the previous tutorial. There is a BIG DIFFERENCE among SQL Server, MySQL and Oracle on update multip...
2016-11-02, 235👍, 0💬

Inserting Multiple Rows with One INSERT Statement in SQL Server
How To Insert Multiple Rows with One INSERT Statement in SQL Server? 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 you a...
2016-11-02, 235👍, 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, 235👍, 0💬

Measuring Performance of INSERT Statements in SQL Server
How To Measure Performance of INSERT Statements in SQL Server? When indexes are defined for a table, each time a new row is inserted to the table, all the indexes must be updated. This extra update work could slow down the insert statement. To find out how much slower the INSERT statements will be o...
2016-11-13, 234👍, 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, 233👍, 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, 233👍, 0💬

"ALTER LOGIN" - Changing the Password of a Login Name in SQL Server
How To Change the Password of a Login Name in SQL Server? If a developer lost the password of his or her login name, you can reset the password with the "ALTER LOGIN" statement as shown in this tutorial example: -- Login with sa ALTER LOGIN FYI_DBA WITH PASSWORD = 'fyicenter'; GO Command(s) complete...
2016-10-20, 233👍, 0💬

Declaring and Using Cursor Variables in SQL Server
How To Declare and Use Cursor Variables in SQL Server Transact-SQL? There are two ways to representing a cursor: 1. A cursor name - A static name representing a cursor object. A cursor name should be linked to a cursor object in the DECLARE statement. 2. A cursor variable name - A variable name poin...
2016-10-17, 233👍, 0💬

List All Existing Databases in MySQL
How To Get a List of Databases from MySQL Servers in MySQL? Once you got a MySQL server connection object successfully, you need to know what databases are available on the server and which database you should use to manage your tables and data. To get a list of all available databases on your MySQL...
2017-11-11, 231👍, 0💬

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