sql - When to use Common Table Expression (CTE) - Stack Overflow
Jan 5, 2017 · There are two reasons I see to use cte's. To use a calculated value in the where clause. This seems a little cleaner to me than a derived table. Suppose there are two tables - Questions and Answers joined together by Questions.ID = Answers.Question_Id (and quiz id)
sql - CTE within a CTE - Stack Overflow
You can't nest CTEs like that in SQL Server but you can use multiple CTEs the following way:;with test as ( select SRnum, gamenumber, StartOfDistribution, ApplicationNumber from #main where startofdistribution = '2011-06-14 00:00:00.000' and SRnum = '313' --order by SRnum, gamenumber, StartOfDistribution, ApplicationNumber ), outertest as ( select …
How can I use if statement after a CTE (SQL Server 2005)
A CTE must be followed by a single SELECT, INSERT, UPDATE, MERGE, or DELETE statement that references some or all the CTE columns. A CTE can also be specified in a CREATE VIEW statement as part of the defining SELECT statement of the view
sql - What are the advantages/disadvantages of using a CTE?
Sep 10, 2008 · The following points are good reasons to use a CTE: A CTE can help you to avoid repeated sub queries. A CTE can be used multiple times within your statement, e.g. within a JOIN with a dynamic behavior depending on the actual row-count. You can use multiple CTEs within one statement and you can use the result of one CTE within a later CTE.
Keeping it simple and how to do multiple CTE in a query
Example C, "Using multiple CTE definitions in a single query," calls this out explicitly. Sadly, this example is not provided in the documentation for SQL 2008 and older (i.e., the example wasn't provided when the OP posted the question). –
CTE inside CTE in SQL Server - Stack Overflow
Apr 10, 2014 · WITH CTE AS ( SELECT * FROM OPENQUERY([Your Server], 'Query Provide by Other System') ) SELECT * FROM CTE; You may need to configure your server for data access: EXEC sp_serveroption 'your server', 'DATA ACCESS', TRUE;
sql - How do I decide if I should use a CTE or not ... - Stack Overflow
Jul 12, 2012 · For simple examples, it doesn't make much difference. If you need to use the Recursive features to build up a hierarchy, then you haven't much choice - you need to use a CTE. Another case where it probably doesn't make much performance difference, but does for readability, is when you need to join the same subquery multiple times.
sql - how to assign cte value to variable - Stack Overflow
Nov 13, 2014 · **/ ) SELECT @YourVariable = FieldNameOrSubquery -- In short: Expression FROM CTE In this case all fields in the SELECT list should be assigned to a variable! Or you can assign a single row-single column SELECT statement's result to a variable by the SET keyword:
sql - Use one CTE many times - Stack Overflow
A CTE is, per definition, only valid for one statement. You can create an inline table-valued function and then use this as often as you like. The inline function does what the name suggest; its query gets to be part of the query using it (in contrast to non-inline functions which are executed separately and used as a rowset).
sql - Update records in table from CTE - Stack Overflow
Correct, except for the fact that he summarizes his question in the title: "Update records in table from CTE". As evidence I'm reading the OP's desire for an answer that involves a CTE, I submit as evidence that he accepted an answer providing a solution using a CTE and that he stated in a follow up comment that he chose a CTE for performance.