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Merge Outputs from Two Queries in MySQL
How To Use UNION to Merge Outputs from Two Queries Together in MySQL? 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 return all links that were created since year 2006 plus the o...
2017-12-21, 1354🔥, 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, 1354🔥, 0💬

Concatenating Character Strings in MySQL
How To Concatenate Two Character Strings in MySQL? If you want concatenate multiple character strings into one, you need to use the CONCAT() function. Here are some good examples: SELECT CONCAT('Welcome',' to') FROM DUAL; Welcome to SELECT CONCAT('FYI','center','.com') FROM DUAL; FYIcenter.com   ⇒ E...
2018-04-07, 1353🔥, 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, 1349🔥, 0💬

Assign Names to Query Output Columns in MySQL
How To Name Query Output Columns in MySQL? Each column in the query output has a default name. If you don't like the default name, you can specify a new name for any column in the query output by using the AS clause. The following statement shows you a good example: mysql&gt; SELECT tag AS Categ...
2017-09-28, 1348🔥, 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, 1347🔥, 0💬

What Are Views in SQL Server
What Are Views in SQL Server? A view is a database object that represents the data in one or more tables in the same structure as a separate table. Here are some basic rules about views: Tables store real data. Views do not store real data. Views must have underlying tables to provide data. Each vie...
2016-11-08, 1346🔥, 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, 1345🔥, 0💬

Update Values in a Table in Oracle
How To Update Values in a Table in Oracle? If you want to update some values in one row or multiple rows in a table, you can use the UPDATE statement. The script below shows a good example: UPDATE fyi_links SET counts = 999, notes = 'Good site.' WHERE id = 101; 1 row updated. SELECT * FROM fyi_links...
2020-01-21, 1344🔥, 0💬

What Is Transaction in MySQL
What Is Transaction in MySQL? A transaction is a logical unit of work requested by a user to be applied to the database objects. MySQL server introduces the transaction concept to allow users to group one or more SQL statements into a single transaction, so that the effects of all the SQL statements...
2016-10-16, 1344🔥, 0💬

Who Is the Owner of a Schema in SQL Server
Who Is the Owner of a Schema in SQL Server? When you create a schema in a database, SQL Server will assign a owner (a database user) to this schema. If your login name is mapped to the owner of a schema at the database level, you have the full permission on all objects in this schema. The following ...
2016-10-22, 1343🔥, 0💬

"DROP FUNCTION" - Dropping an Existing User Defined Function in SQL Server
How To Drop an Existing User Defined Function in SQL Server Transact-SQL? If you have an existing user defined function that you don't want to use it anymore, you should delete it from the SQL Server by using the "DROP FUNCTION" statement as shown in the tutorial example below: USE FyiCenterData; GO...
2016-12-24, 1341🔥, 0💬

Counting Groups Returned with the GROUP BY Clause in SQL Server
How To Count Groups Returned with the GROUP BY Clause in SQL Server? If you use the COUNT(*) function on groups returned with the GROUP BY clause, it will count the number of rows within each group, not the number of groups. If you want to count the number of groups, you can put the GROUP BY query i...
2016-10-29, 1340🔥, 0💬

Using Group Functions in the ORDER BY Clause in SQL Server
Can Group Functions Be Used in the ORDER BY Clause in SQL Server? If the query output is aggregated as groups, you can sort the groups by using group functions in the ORDER BY clause. The following statement returns the maximum "counts" in each group, determined by a unique combination of tag and ye...
2016-10-25, 1339🔥, 0💬

Converting Character Strings to Dates in MySQL
How To Convert Character Strings to Dates in MySQL? If you have a character string that represents a date, and you want to convert it into a date value, you can use the STR_TO_DATE(string, format) function. STR_TO_DATE() shares the same formatting codes with DATE_FORMAT() function. The tutorial exer...
2017-12-26, 1338🔥, 0💬

Writing Inner Joins with the WHERE Clause in SQL Server
How To Write an Inner Join with the WHERE Clause in SQL Server? If you don't want to use the INNER JOIN ... ON clause to write an inner join, you can put the join condition in the WHERE clause as shown in the following query example: SELECT l.id, l.url, r.comment FROM fyi_links l, fyi_rates r WHERE ...
2016-10-29, 1338🔥, 0💬

Writing Date and Time Literals in MySQL
How To Write Date and Time Literals in MySQL? MySQL offers a number of formats for you to use to enter date and time literals: ANSI standard format: "YYYY-MM-DD HH:MM:SS". Non-standard limiters. Like: "YYYY/MM/DD HH^MM^SS" or "YYYY.MM.DD HH-MM-SS". No limiters. Like: "YYYYMMDD" for a date or "HHMMSS...
2017-12-26, 1336🔥, 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, 1332🔥, 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, 1331🔥, 0💬

LIKE - Matching a Pattern in a Character String in SQL Server
What To Perform Pattern Match with the LIKE Operator in SQL Server Transact-SQL? Pattern match is a very important operation for search records base on character string columns. SQL Server 2005 offers the LIKE operator to perform pattern match operations in two formats: target_string LIKE pattern --...
2017-01-21, 1329🔥, 0💬

SQL Server Connection Tutorials
Where to find SQL Server Connection tutorials? I am having trouble to connect to my SQL Server. Here is a collection of tutorials, tips and FAQs on how to connect your client tools and client application programs to SQL server. SQL Server Connection Concepts SQL Server Connection Protocols SQL Serve...
2023-12-30, 1328🔥, 0💬

Updating Values in a Table in MySQL
How To Update Values in a Table in MySQL? 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: mysql&gt; UPDATE fyi_links SET counts = 999, notes = 'Good.' WHERE id = 101; Query OK, 1 row affec...
2018-01-13, 1328🔥, 0💬

Running SQL Server 2005 Books Online on Your Local System in SQL Server
How to run SQL Server 2005 Books Online on your local system in SQL Server? SQL Server 2005 Books Online can be accessed by a Web browser over the Internet. But you can also download it and read it on your local system. If you have downloaded and installed SQL Server 2005 Books Online package, you f...
2016-12-04, 1328🔥, 0💬

DROP INDEX - Removing Existing Indexes in SQL Server
How To Drop Existing Indexes in SQL Server? For some reason, if you want remove an existing index, you can use the DROP INDEX statement with following syntax: CREATE INDEX table_name.index_name The tutorial exercise below shows you how to remove the index "fyi_links_id": USE FyiCenterData; GO SELECT...
2016-11-15, 1327🔥, 0💬

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