SQL

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From SQL to DAX: Joining Tables

In SQL there are different types of JOIN, available for different goals. This article shows what are the equivalent syntaxes supported in DAX.

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From SQL to DAX: IN and EXISTS

The SQL functions IN and EXISTS are useful to implement tests over a set of values. This article describes the corresponding syntax in DAX language.

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From SQL to DAX: Grouping Data

The GROUP BY condition of a SQL statement is natively implemented by SUMMARIZE in DAX. This article shows how to use SUMMARIZE and an alternative syntax to group data.

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From SQL to DAX: Filtering Data

The WHERE condition of an SQL statement has two counterparts in DAX: FILTER and CALCULATETABLE. In this article we explore the differences between them, providing a few best practices in their use.

WHITEPAPER

VertiPaq vs ColumnStore Comparison

SQL 2012 gives you two different xVelocity engines, with different capabilities and different scenarios of implementation, the paper will help you choose the right one or, at least, raise your curiosity about performing more tests on your specific scenario.

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From SQL to DAX: String Comparison

In DAX string comparison requires you more attention than in SQL, for several reasons: DAX doesn’t offer the same set of features you have in SQL, a few text comparison functions in DAX are only case-sensitive and others only case-insensitive, and performance might have a relevant impact in your query

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From SQL to DAX: Projection

Using DAX as a query language you will lack a fundamental feature like projection. In fact, DAX allows you add columns to an existing table, but you cannot simply remove some column from a table. In order to do that, you have to use SUMMARIZE, or you can use ADDCOLUMNS

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SSIS: living in a parallel world? Not yet…

Today I come into a nice bug (misfeature?) of SSIS 2008 and I’d like to share it with you. Let’s start from the beginning: One of the keys to make something speedy is to parallelize it. In TableDifference I read from two inputs, compare them and produce

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Visio and SQL Extended Properties: a tool to marry them

Visio database models have column descriptions, SQL Server has extended properties where to store them but, even if they share the same producer, it seems that Visio is unable to store column descriptions in extended properties so that other tools can

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SQL: Merge two "history tracking" tables

If you have two columns in a table that “remember” their old values in two different historical tables, as it is the case in AdventureWorks with EmployeePayHistory and EmployeeDepartmentHistory, you may need (or just wonder how) to merge these two tables