mbergstrom (5/29/2009)

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How does the ROW_NUMBER() approach compare with using self-joins as follows?

SELECT Previous.Category,
	Previous.Date,
	Next.Date
FROM Dates.CategoryDate Previous
LEFT JOIN Dates.CategoryDate Next
	ON Previous.Category = Next.Category
	AND Previous.Date < Next.Date
LEFT JOIN Dates.CategoryDate Middle
	ON Previous.Category = Middle.Category
	AND Previous.Date < Middle.Date
	AND Middle.Date < Next.Date
WHERE Middle.Category IS NULL;

FreeHansje (6/2/2009)

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Very educational article. Lately I have to deal with performance issues created by similar queries as given in this article. I like to read more about subqueries and their alternatives. For instance, could row_number be used to search in a string-column of a table? I now have something like:

DECLARE @var1 AS String, @var2 AS String
SELECT c1, c2, c3 FROM Table
WHERE StringColumn LIKE '%' + @var1 + '%' AND StringColumn LIKE '%' + @var2 + '%'

I'm trying several aproaches and I'm sure I'll either figure it out or conclude it can't be made pretty.

Tnx again.

FreeHansje (6/2/2009)

---

Very educational article. Lately I have to deal with performance issues created by similar queries as given in this article. I like to read more about subqueries and their alternatives. For instance, could row_number be used to search in a string-column of a table? I now have something like:

DECLARE @var1 AS String, @var2 AS String
SELECT c1, c2, c3 FROM Table
WHERE StringColumn LIKE '%' + @var1 + '%' AND StringColumn LIKE '%' + @var2 + '%'

I'm trying several aproaches and I'm sure I'll either figure it out or conclude it can't be made pretty.

Tnx again.

FreeHansje (6/2/2009)

---

Very educational article. Lately I have to deal with performance issues created by similar queries as given in this article. I like to read more about subqueries and their alternatives. For instance, could row_number be used to search in a string-column of a table? I now have something like:

DECLARE @var1 AS String, @var2 AS String
SELECT c1, c2, c3 FROM Table
WHERE StringColumn LIKE '%' + @var1 + '%' AND StringColumn LIKE '%' + @var2 + '%'

I'm trying several aproaches and I'm sure I'll either figure it out or conclude it can't be made pretty.

Tnx again.