The SELECT reserved word is part of the Data Manipulation Language (DML) defined by Codd and is used to query data from the database. Because of its popularity, there are many clauses and functions that can be used to construct a query to retrieve data. Today, I am continuing our exploration of this reserved word by reviewing queries that merge data using the APPLY operator. The APPLY operator come in two flavors: CROSS and OUTER. I am going to concentrate on the later during this discussion. I will be using…
Tag: correlated sub-query
Cross Apply Operator
The SELECT reserved word is part of the Data Manipulation Language (DML) defined by Codd and is used to query data from the database. Because of its popularity, there are many clauses and functions that can be used to construct a query to retrieve data. Today, I am continuing our exploration of this reserved word by reviewing queries that merge data using the APPLY operator. The APPLY operator come in two flavors: CROSS and OUTER. I am going to concentrate on the former during this discussion. I will be using…
Selecting Data – Part 4
Today, I am continuing our exploration of the SELECT reserved word by talking about sub-queries. A sub-query is a query that is nested inside a SELECT, INSERT, UPDATE, or DELETE statement, or inside another sub-query. Sub-queries can be used anywhere an expression is allowed or can be nested inside another sub-query. I will be using the AdventureWorks Sample database supplied by Microsoft during this talk.
|
1 2 3 4 |
<span style="color: #008000; font-family: Lucida Console; font-size: small;">-- Use the correct database USE AdventureWorks2008R2 GO </span> |
One usage a sub-query is with comparison operators in the where clause. The example below returns all the sales people by name and id…