SQL aggregate functions AVG, COUNT, MAX, MIN, SUM are used the most. That is because we often need to add, make average or find the highest or lowest value. It is mandatory to use GROUP BY clause anytime when we use aggregate function. (except for operations over windows using OVER()) List of SQL Server Aggregate… Read More »
SQL ranking functions enable us to rank records in the table based on values of a field or multiple fields. Clause OVER() is mandatory for the ranking functions. Ranking functions belongs to the group of Window functions. Aggregate functions and Offset functions (for paging) also belong to this group. List of Ranking Functions ROW_NUMBER ()… Read More »
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 »
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 »
WHERE clause is used to define limit requirements for queries. We are not interested in all records in most cases of queries into tables. Only some subsets of the records based on set criteria are of our interest. Order of WHERE Clause in SQL Script SELECT FROM WHERE GROUP BY HAVING ORDER BY Syntax SELECT… Read More »
In Excel, we work mostly with numbers (aggregation via SUM, AVERAGE, etc.) or with dates. However, it is true that very often we need to adjust, combine or clean text columns. There are many situations where we want to edit the text in some way (it cannot be generalized). It depends on a case-by-case, but… Read More »
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 »
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 »
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 »
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 »