General MySQL Oracle SQL Server

<< < … 10 11 12 13 14 15 16 17 18 19 20 … > >>   ∑:509  Sort:Date

CREATE INDEX - Adding an Index on an Existing Table in SQL Server
How To Create an Index on an Existing Table in SQL Server? If you want to an index on an existing table, you can use the CREATE INDEX statement in a simple syntax: CREATE INDEX index_name ON table_name (column_name) The tutorial exercise below shows you how to add an index for the "in" column of the... 2016-11-15, 2327🔥, 0💬

Deleting a Table That Is Used by a View in SQL Server
What Happens If You Delete a Table That Is Used by a View in SQL Server? Assuming that you have a table which is used by a view, and you try to delete that table. SQL Server will let you delete the table without any trouble. But that view will become invalid. The tutorial exercise below shows you wh... 2016-11-04, 2327🔥, 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, 2325🔥, 0💬

Sorting Query Output in Descending Order in SQL Server
How To Sort Query Output in Descending Order in SQL Server? 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: SELECT tag, cou... 2016-10-26, 2325🔥, 0💬

Overflow Errors on Converting Big Values to Integers in SQL Server
What Happens When Converting Big Values to Integers in SQL Server Transact-SQL? If you are converting a numeric expression to an integer data type and the value is too big for integer storage size, you will get an arithmetic overflow error as shown in the following examples: -- Overflow error on imp... 2017-03-22, 2324🔥, 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, 2323🔥, 0💬

Duplicate Key Error on Primary Key Columns in SQL Server
What Happens If You Insert a Duplicate Key for the Primary Key Column in SQL Server? If your table has a primary key column, and you are trying to insert a new row with duplicate key value on the primary key column, you will get an error. The reason is simple - Primary key column does not allow dupl... 2016-11-02, 2323🔥, 0💬

Getting Month and Weekday Names from DATATIME Values in SQL Server
How To Get Month and Weekday Names from DATETIME Values in SQL Server Transact-SQL? In DATETIME values, the month part and weekday part have names. You can use the DATENAME() function to get the month name and weekday name from a DATETIME value in the following format: DATENAME(datepart, date) retur... 2017-02-14, 2321🔥, 0💬

"CREATE TRIGGER" - Creating a DML Trigger in SQL Server
How To Create a DML Trigger using CREATE TRIGGER Statements in SQL Server? A DML trigger is a trigger declared to handle a DML event, which occurs when an INSERT, UPDATE or DELETE statement is executed. If you want to create a DML trigger, you should use the "CREATE TRIGGER" statement in the followi... 2016-10-25, 2321🔥, 0💬

Performing Comparison on Floating Point Numbers in SQL Server
How To Perform Comparison on Floating Point Numbers in SQL Server Transact-SQL? Comparison operations on approximate (floating point) numbers are also easy to understand. Just watch out rounding operations performed during conversions. Here are two examples of floating point number comparisons: -- R... 2017-01-21, 2320🔥, 0💬

What Is a Database in SQL Server
What is a database in SQL Server? A database is a logical container that contains a set of related database objects: Tables - Storages of structured data. Views - Queries to present data from tables. Indexes - Sorting indexes to speed up searches. Stored Procedures - Predefined SQL program units. Us... 2016-11-24, 2318🔥, 0💬

Adding a New Index to a Large Table in SQL Server
What Happens If You Add a New Index to Large Table in SQL Server? An index can be added when you create a new table. New rows will be indexed as they are inserted into the table. But you can also add a new index to an existing table with the same CREATE INDEX statement. The existing rows will be ind... 2016-11-13, 2318🔥, 0💬

Updating Values with UPDATE Statements in SQL Server
How To Update Values in a Table with UPDATE Statements in SQL Server? If you want to update some values in one row or multiple rows in a table, you can use the UPDATE statement. The tutorial script below shows a good example: SELECT * FROM fyi_links WHERE id = 101 GO id url notes counts created 101 ... 2016-11-02, 2317🔥, 0💬

SINGLE_USER/MULTI_USER - Database User Access Options in SQL Server
How to set database to be SINGLE_USER in SQL Server? Databases in SQL Server have three user access options: MULTI_USER - All users that have the appropriate permissions to connect to the database are allowed. This is the default. SINGLE_USER - One user at a time is allowed to connect to the databas... 2016-11-20, 2314🔥, 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, 2313🔥, 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, 2312🔥, 0💬

Rebuilding All Indexes on One Table in SQL Server
How To Rebuild All Indexes on a Single Table in SQL Server? If you have several indexes on a single table and want to rebuild all of them, you may use the "ALTER INDEX ALL ON table_name REBUILD" statement as shown in the tutorial exercise below: USE FyiCenterData; GO UPDATE fyi_links_indexed SET url... 2016-11-08, 2311🔥, 0💬

Using Subqueries in the FROM Clause in SQL Server
How To Use Subqueries in the FROM Clause in SQL Server? 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 yo... 2016-10-29, 2308🔥, 0💬

SQL Server Connection Concepts
Where to find answers to frequently asked questions on SQL Server Connection Concepts? Here is a list of frequently asked questions and their answers compiled by FYIcenter.com DBA team on SQL Server Connectivity Concepts. SQL Server Connection Protocols SQL Server TCP/IP Connection Info   ⇒ SQL Serv... 2024-08-14, 2302🔥, 0💬

Performing Comparison on Character Strings in SQL Server
How To Perform Comparison on Character Strings in SQL Server Transact-SQL? Comparison operations on character strings are performed based on the associated collation. Each collation defines rules on how characters are ordered, how character cases and accents are treated, etc. The tutorial exercise b... 2017-01-21, 2301🔥, 0💬

OUTPUT - Receiving Output Values from Stored Procedures in SQL Server
How To Receive Output Values from Stored Procedures in SQL Server Transact-SQL? If an output parameter is defined in a stored procedure, the execution statement must provide a variable to receive the output value in the format: "@variable_name OUTPUT" or "@parameter_name = @variable_name OUTPUT". Th... 2016-12-28, 2300🔥, 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, 2299🔥, 0💬

"DROP SCHEMA" - Dropping an Existing Schema in SQL Server
How To Drop an Existing Schema in SQL Server? If you want to delete a schema, you need to move all objects out of that schema, then use the "DROP SCHEMA" statement to delete the schema. The tutorial exercise below shows you how to drop schema "fyi": -- Login with "sa" USE FyiCenterData; GO -- Drop f... 2016-10-20, 2297🔥, 0💬

"CREATE USER" - Creating a User Name in a Database in SQL Server
How To Create a User Name in a Database in SQL Server? User names are security principals at the database level. If you want to allow a login name to access a specific database, you need to create a user name in that database and link it to the login name. Creating a user name can be done by using t... 2016-10-19, 2295🔥, 0💬

<< < … 10 11 12 13 14 15 16 17 18 19 20 … > >>   ∑:509  Sort:Date

General MySQL Oracle SQL Server