# Author Archives: Jan Zedníček

My name is Jan Zedníček and I work as a freelancer. I have been working as a freelancer for many companies for more than 5 years. I used to work as a financial controller, analyst and manager at many different companies in field of banking and manufacturing. When I am not at work, I like playing volleyball, chess, doing a workout in the gym and I enjoy tasting of best quality rums. I am trying to summarize all my knowledge on this website not to forget them (because of the rum effect, you know =) and to put them forward to anyone. Don´t worry about asking for help or writing some comments.

## Sales Report in Power BI and Direct Query into SQL Database

By | 23. 5. 2020

Whenever we set connector to our data in Power BI, we have an option to select connection to a certain object (e.g. a table) or there is a second option. That is connection using direct query which secures live connection to data source. We will prepare simple Sales report by few clicks. (as in video).… Read More »

## AND, OR Logical Functions in Excel

By | 23. 5. 2020

Logical functions serve us to test conditions not only in Excel. They can be used in situation when we need to compare 2 or more values and find out if a certain condition is met. Often used function IF belongs to logical functions, except for this function, you will most often use functions AND and… Read More »

## Excel | Subtotal – 11 Functions in One

By | 23. 5. 2020

SUBTOTAL is a little strange function. There are 11 mathematical functions hiding inside it. We can calculate sum, arithmetic mean, spread, minimum/maximum and another statistic values using SUBTOTAL function. What’s more, we can limit whether we want to calculate even with hidden values which were hidden manually. All under roof of one function. SUBTOTAL –… Read More »

## Excel – Function for date and time – YEAR, MONTH, DAY, HOUR, MINUTE, SECOND

By | 23. 5. 2020

There is a huge number of functions for date and time in Excel. they are used to extract parts of the date or time type of cell. You may have needed to extract some certain parts of the data of date and time data types, for example month. All functions have identical and absolutely simple… Read More »

## Power BI Gateway – Introduction Into Tool For Report Refresh/Update

By | 23. 5. 2020

It is nothing hard to create report using Power BI desktop for example from Excel and then upload it to the cloud on powerbi.com. But how to update the cloud data when the source file is located on your PC/server and “the cloud service does not see the data”? One of the ways is to… Read More »

## Connecting to SQL Server | Power Query

By | 23. 5. 2020

It is possible to connect to many data sources using Power Query (more in this article) and SQL Server database is one of them. This article will tell you how to set connection to SQL Server table directly from Excel in few simple steps. Guide to Data Import and Connecting to SQL Server from Excel… Read More »

## Power BI Refresh Does Not Work – Reason?

By | 23. 5. 2020

Did it ever happen to you that the Power BI update did not work? There might be several reasons for this problem and it is always user’s fault. We will model a few of these situations on a timesheet. Our goal is to find out why the report refresh does not perform without an error.… Read More »

## WEEKNUM, ISOWEEKNUM,WEEKDAY Excel – Was it on Friday After 15th Week of The Year?

By | 21. 3. 2020

You have a huge table with many date entries in it. You need to find out which date is after 20th week of the year or if a certain date is Friday. MS Excel will help by three functions – WEEKNUM, ISOWEEKNUM,WEEKDAY . It is definitely more effective than searching in calendar. More so if… Read More »

## FILTER Functions for Power BI in DAX – Overview

By | 21. 3. 2020

FILTER functions (filtering functions) are used to get values from the table. Some functions enable additional filtering in a given table. These functions are often part of different functions as is nested parameter and enable dynamic calculations. They often serve as a value filter for function  CALCULATE. Mostly it is the case of typical member… Read More »

Category: DAX

## Aggregation in DAX – How Aggregations Work? + Function Overview

By | 21. 3. 2020

Aggregate functions in DAX language are used to get certain summarized or grouped data view. Thanks to this, we can edit high detail data in a certain column into more simple and reportable form using aggregation. We can for example sum up (SUM, SUMX) some financial metrics by individual category or express maximal/minimal (MAX, MAXX,… Read More »

Category: DAX

## Function DAX CALCULATE – Aggregation With a Condition in Power BI

By | 21. 3. 2020

CALCULATE is an important function for a large number of calculations and for those of you who actively do DAX formulas in Power BI or PowerPivot. Understanding of how the function works and how it is used does not look simple at first glance. And that is why this article is here. Syntax function: CALCULATE(… Read More »

Category: DAX

## DAX RELATED Function for Power BI – Lookup Into Table

By | 21. 3. 2020

Function REALTED is very frequent and useful in DAX language. We can use it for example when we need to search table (A) for value from other table (B). And finding the according value is the exact task of this function. Syntax is very simple: How Come RELATED Function Needs Only 1 Parameter? Data organization… Read More »

Category: DAX

## SQL ROLLUP, CUBE, GROUPING SETS – Totals and Subtotals

By | 15. 2. 2020

What about upgrading GROUP BY clause by use of useful commands? GROUP BY is used in a clause with aggregate operations. When it is used, aggregation happens throughout all columns. Using this simple “grouping” does not enable us to do totals and subtotals. But there is plenty of operators which can easily query for totals.… Read More »

## DAX | SUM and SUMX – How to Perform Aggregation in DAX Language for Power BI

By | 11. 2. 2020

You probably noticed that there are many functions in DAX that are similar to Excel ones (as in article here). Contrary to Excel functions, DAX haves on strange thing. Some aggregate functions have another similar function ending with X – for example SUM and SUMX or COUNT and COUNTX. These functions often give same results… Read More »

## SQL Indexes – Indexing Theory Simply, Balanced Tree, Heaps

By | 11. 2. 2020

Correct table indexing in SQL Server is a base for good database performance during querying. You need to understand how SQL Server stores data into tables/indexes if you want to create appropriate sql indexes. It is also important to know how to approach these data correctly during querying. How Does SQL Server Organize Data Physically?… Read More »

## DAX Difference Between Measure and Column + Example on Report

By | 11. 2. 2020

We can create two types of new values using DAX in Power BI or PowerPivot. They are calculated measures and columns. Difference between measure and column and its understanding is another major step in order to understand DAX language for Power BI. New measure or column in Power BI is added by clicking right mouse… Read More »

## DAX language – Introduction into DAX for Power BI and Powerpivot

By | 11. 2. 2020

DAX language (Data Analysis Expressions) servers for data management and editing prior reporting in Power BI or Powerpivot, similarly to function set in Excel. This language is able to return values based on use of functions. We can either enrich, add or analyze data prior reporting in Excel, and DAX enables us to do the same.… Read More »

By | 11. 2. 2020

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## Parameters in DAX – Introduction into DAX Expressions

By | 11. 2. 2020

DAX language haves its standards as does any other language. This article sums up and describes how look the parameters of formulas. In other words, this article is about function arguments overview.  It is good to know parameter categories appearing in this language to effectively use parameters in DAX. What is Function Parameter in DAX?… Read More »

## Basic SQL Queries – Overview For Beginners With Examples

By | 3. 2. 2020

What I have here today is a article for beginners. It will be full of sql query examples. We will start from the most basic ones and continue up. SQL queries will be organized chronologically according to their difficulty. I will add more later on. SQL knowledge is a must for any IT department nowadays.… Read More »