Performance Tuning Tips: Explore best practices for optimizing SQL query performance. Regular Expressions in SQL: Learn how to use regular expressions for pattern matching within SQL queries. Exercises, Interview Questions & Cheat Sheet Hands-On Practice Strengthen your SQL skills with practical exercises...
TheWHEREclause is essential in SQL queries because it allows us to filter data based on specific conditions, ensuring only relevant records are returned. It improves query efficiency by reducing the amount of data processed, which is very important for working with a large dataset. ...
Thereby, the following query lines can stay unchanged. Then, we construct two similar queries aliased dataset_1_only and dataset_2_only in order to keep rows that are only present in dataset 1 (compared with dataset 2) and vice-versa thanks to the EXCEPT set operator. Finally, a ...
A little background for those new to using Power BI and Data Gateways. If the data source for your Power BI dataset lives on-prem or behind a private endpoint, you will need a Data Gateway to access the data. If you want to keep your data fresh (either using Direct Query or Import ...
Begin Transaction with If Condition BEGIN TRANSACTION within TRY - CATCH or vice versa Best practice to handle the paging and performance in SQL Stored procedure Best Practice: Use of semi-colon to terminate statements; Best practices in writing queries for huge dataset Best way to delete 311 mil...
Looking to level up your SQL skills? Here's a list of the best platforms to practice SQL, ace your SQL interviews, and land your dream data role. SQL SQL With CSVs- Jan 5, 2023. Write SQL query to analyze CSV files using the simple command line tool. ...
Nevertheless, using the AS keyword is always a good practice. SELECT A.emp_name AS "Employee" /* Alias using AS keyword */ B.emp_name AS "Supervisor" FROM employee A, employee B /* Alias without AS keyword */ WHERE A.emp_sup = B.emp_id; Write an SQL statement to select all ...
Start small, and find a project using SQL to play with. Once you get comfortable, familiarize yourself with a real-life dataset that interests you and use a database to play around. Daily coding practice with this will improve your skills and help you search out answers as you go. Not...
Jump-start your career as a data scientist鈥攍earn to develop datasets for exploration, analysis, and machine learning SQL for Data Scientists: A Beginner's Guide for Building Datasets for Analysis is a resource that's dedicated to the Structured Query Language (SQL) and dataset design skills ...
When used within a query, the COUNT function returns a numeric value. You can also use the COUNT function with the DISTINCT command to only count the distinct rows of a dataset. ALL (opposite of DISTINCT) is the default; it is not necessary to include ALL in the syntax. Duplicate rows ...