articles inner-source 
SQL Performance
SEPTEMBER 8, 2021
This article is the eleventh part in a series about table expressions. In Part 9 I compared views to derived tables and CTEs, and in Part 10 I discussed DDL changes and the implications of using SELECT * in the view’s inner query. In this article, I focus on modification considerations. Sample Data. FastOrders.
SQL Performance
MAY 13, 2020
For example, the expression can be a table value constructor, as I will explain later in this article. With table expressions you can reuse aliases that you define in an inner query in any clause of the outer query, and this way avoid repetition of lengthy/complex expressions. I'll get to this one later in the article.
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SQL Performance
AUGUST 12, 2020
This article is the fifth part in a series about table expressions. The source of the term aside, common table expression , or CTE , is the commonly used term by T-SQL practitioners for the structure that is the focus of this article. Of course, I’ll demonstrate this design aspect in this article. The outer query.
SQL Performance
SEPTEMBER 25, 2019
Performance spools are lazy spools added by the optimizer to reduce the estimated cost of the inner side of nested loops joins. An example plan shape showing a lazy table performance spool is below: The questions I set out to answer in this article are why, how, and when the query optimizer introduces each type of performance spool.
SQL Performance
MAY 11, 2022
You can download the source code to create and populate this database here. In this article, I want to focus on tips having to do with the potential of the window function’s calculation in the plan to rely on ordered input data without requiring an extra explicit sort activity in the plan. FROM C1 INNER JOIN C2 ON C1.
SQL Performance
JUNE 14, 2019
This article is the third installment in a series about T-SQL bugs, pitfalls and best practices. In this article I focus on four classic common bugs: COUNT(*) in outer joins, double-dipping aggregates, ON-WHERE contradiction and OUTER-INNER join contradiction. Orders AS O INNER JOIN Sales. This time I focus on joins.
SQL Performance
NOVEMBER 22, 2019
To be accessed more than once, the spool must appear on the inner side of a nested loops join operator. For the difference between the two, please see my article Apply versus Nested Loops Join. For the difference between the two, please see my article Apply versus Nested Loops Join. Notable features. ProductID , P. [
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