When we work with SQL database we usually need to work with 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… Read More »
SELECT clause is used to gain data from a table. This clause is followed by a list of columns, which we need to display. This clause must always be used in combination with clause FROM by which we state from which table we want the data to be selected. Ideally, we also add clause WHERE… Read More »
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 »
Loop is a repeated call of a part of a code with different parameters. Usually the code is bound to certain DML operation such as INSERT or UPDATE. We call out this cycle for predetermined number of repetitions and it can be built in SQL in different ways. We will take a look at all… Read More »
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 »
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 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 choose (INSERT INTO … VALUES (value1, value2, …)) You can insert the values into the table using script (SELECT clause… Read More »
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 »
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 »
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 »