How often do we think of NULL values while concatenating NULLs with string values? String concentration with NULL values can give us some unexpected results if we are not aware of CONCAT_NULL_YIELDS_NULL database SET options. CONCAT_NULL_YIELDS_NULL options control whether concatenation results shall be treated as NULL or empty string values.

To learn the basics of SQL Server, you must have an understanding of how an SQL Server query engine executes an SQL query. T-SQL involves both logical and physical query processing. Physical query processing is about how a database engine processes a query. Logical query processing is a conceptual flow, an order of the clauses […]

SQL Server has introduced multiple ways to handle NULL values. The functions that are most used to handle NULLs are COALESCE and ISNULL in SQL Server. These functions are used to find Non-NULL values from a list of arguments. In this post, we will see the uses of the ISNULL and COALESCE functions and their […]

SQL Server has supported SEQUENCE objects since the inception of SQL Server 2012 and later editions. Oracle database has supported SEQUENCE objects from the beginning. You can read the archive post on Tech-Recipes using SEQUENCE in Oracle.

Every developer likes to work on a code that is thoroughly documented with documentation that makes sense and provides adequate insight and information to understand the code’s functionality. Most programming languages provide special tools to generate documentation. For example, the JavaDoc tool is used for generating API documentation in HTML format from available doc comments […]

Let’s assume you are constructing a new house, and you have a contract with a builder. After thoughtful examination of the area, height, and materials needed, he estimates it will take 120 days to build a new home. After constructing the home, it actually took 200 days to built it. There is a difference between […]

We have all heard the horror stories: You receive a late night call from the office, the caller frantically telling you that the entire network has gone down and the backups are corrupted, or even worse, missing entirely. The IT landscape is littered with tales of backups gone wrong, both deliberately and accidentally. Businesses have […]

SQL Server is an all-in-one IDE for managing multiple user instances, SQL programming, and changing settings using graphical options. Often, we need to find out when a stored procedure/trigger was last modified, or we need to find the creation date of existing objects in SQL server. Finding the creation dates and the modification dates of […]

While querying the production server to solve one critical issue, suddenly one query completely caught my attention. We had written a query which was created to find records which exist in Table A but do not exist in Table B, based on a certain column. The query was syntactically correct and ran without any errors, […]

Based on what I have heard from friends and other online users and from my own personal experience, the most common job interview question for database programmers is “How do you find the highest salary in an employee table?” This question tests a candidate’s knowledge of ranking functions, subqueries, common table expression (CTE) and basic […]

During my schooling, one of my teachers said, “A friend of mine scored 105 on a science test out of 100. I was wondering how it is possible to score 105 out of 100. In this case, the value was inflated. Later, it was revealed that the score was a miscalculation. His score was 97. […]

Inner join is used to select rows from multiple tables based on a matching column in one or more tables. It compares each row value of a table with each row value of another table to find equal values. If equal value are found in multiple columns from multiple tables, they are returned in the […]