SQL ORDER BY – Sorting Data in SQL Table in Descending or Ascending Order

ORDER BY clause in SQL enables us to sort results of the query by specific field (column) or more columns. There are 2 sorting options: Ascending order (ASC) – sorts records from lowest to highest in case of numbers and from A to Z in case of text strings Descending order (DESC) – sorts records… Read More »

SQL OFFSET Functions – LAG, LEAD, FIRST_VALUE, LAST_VALUE

OFFSET functions are relatively new to MS SQL Server. They are available since SQL Server 2012 version. These functions enable a user to “list” through rows of a table. To be precise, it makes you able to put hand on previous or next row while still at the current one. These functions belong to a… Read More »

Excel | VLOOKUP vs HLOOKUP – What’s the Difference + Example

The VLOOKUP function is one of the most commonly used Excel functions in general. This function returns a value we are looking for from a particular column of a table containing many rows and columns. The function supports 2 modes – full and approximate match. In addition to the VLOOKUP function, there is a similar… Read More »

SQL LEFT OUTER JOIN – Joining tables in SQL With Explanation in Excel

When you work with SQL database you usually need more than 1 table. Some values are in one table and the others are in a different one = division of the information into many tables which are connected between each other (via keys) is the principle of relational database. There are 5 basic kinds of… Read More »

SQL RIGHT OUTER JOIN – Joining Tables in SQL With Explanation in Excel + Example

When you work with SQL database you usually need more than 1 table. Some values are in one table and the others are in a different one = division of the information into many tables which are connected between each other (via keys) is the principle of relational database. There are 5 basic kinds of… Read More »

SQL INNER JOIN – Joining Tables in SQL With Explanation in Excel + Examples

When you work with SQL database you usually need more than 1 table. Some values are in one table and the others are in a different one = distribution of data into many tables which are connected between each other (via keys) is the principle of relational database. There are 5 basic kinds of joins:… Read More »

SQL SELECT DISTINCT – Removing Duplicates from Table = Unique values

SELECT DISTINCT is a command used to show unique records in a table. Its use is broad but it is mainly used to remove duplicities in the records when taking multiple views on data. Hint: If we select more than 1 column, DISTINCT will return unique combinations of selected columns SELECT DISTINCT Syntax Syntax is… Read More »

How to Get Started With Power BI + BI Tools for Excel

Power BI is a cloud technology by Microsoft which enables user to analyze and visualize data easily. Creating reports is a task anyone can do. You do not have to be a programmer to use this tool. You will need just the basic user skills. Undeniable advantage is an ever-growing community, meaning that if a… Read More »

T-SQL Online Quiz – For beginners

Today I have prepared for you a SQL quiz designed for beginners. Successful completion of this quiz should be routine for those of you who work with SQL daily. This T-SQL Online Quiz contains 15 questions and requires at least 70% correct answers to complete it successfully. The difficulty of the test is slightly increased… Read More »

Excel | Mean (Average) Functions Overview – Types, Formulas, Explanation and Examples

Let’s start with what the average means. In terms of descriptive statistics, the average is a certain reference (typical) value. It is a property of the data set that we are investigating. It belongs to the so-called measures of central tendency. If we have a large amount of data, we can describe the data with… Read More »

SQL INSERT – Inserting Rows into Database Table (3 methods) + Common mistakes

SQL Command INSERT is suitable for situations when we want to insert entries into the table. Insertion of rows can be done in multiple ways (further description below): You can insert the values that you fixedly choose (INSERT INTO … VALUES (value1, value2, …)) You can insert the values into the table using script (SELECT… Read More »

SSIS | Data Flow Task for Beginners – ETL Data Pump Component with Example

In the last article, I introduced the Control Flow feature. Using control flow we can manage through tasks what SSIS package does. The most frequently used is a Data flow task, which contains data transfer logic (ETL processes). Difference between Control Flow and Data flow task Unfortunately, these 2 terms are often confused. Control flow… Read More »

SSIS | Control Flow – Tasks, Containers and Data Flow – Integration Services (Beginners)

Before introducing Control Flow, let me recap the previous tutorial SSIS | Introduction, BIDS, Project, Package, SSIS Toolbox where I introduced the SQL Server Integration Services (SSIS) feature for SQL Server. My goal was to show beginners a working environment in which we can develop strong data integrations (ETL). Summary of the previous article –… Read More »

SSIS | Integration Services for Beginners – Introduction, BIDS, Project, Package, SSIS Toolbox

This article serves as an introduction to SQL Server Integration Services (SSIS) for SQL Server. It contains information about this function and its basic parts. SQL Server is generally understood mainly as a database platform containing a powerful database engine and client – Management Studio for working with databases. There are a number of editions,… Read More »

Day Count Convention (Fractions) for Bonds, Loans, Accrued Interest – Financial Mathematics

Most calculations in the area of financial mathematics are relatively easy – for example, to calculate an annuity payment, interest rate or target amount value with regular deposits. However, financial calculations can be quite complex in certain circumstances. This is particularly true on the money and capital markets (bonds) or on some specifically agreed corporate… Read More »