#

window-functions

SQL window functions like ROW_NUMBER()

DatabasesSQL Server Latest Record Per Employee Without OUTER APPLY

Optimize SQL Server queries to get latest attendance records per employee without OUTER APPLY. Use ROW_NUMBER() or MAX() JOIN for better performance.

1 answer• 1 view
ProgrammingPySpark: Merge Consecutive Rows by PersonID & JobTitleID

Learn to merge consecutive rows in PySpark DataFrames by PersonID where JobTitleID matches, using pyspark window functions and groupby pyspark to extend pyspark timestamp from min to max. Scalable gaps-and-islands solution with code examples.

1 answer• 1 view
DatabasesOracle SQL: Get Max Date Row Per UserId (Latest Record)

Learn Oracle SQL techniques to fetch rows with maximum Date per UserId. Use ROW_NUMBER window function, JOIN subquery, NOT EXISTS, or KEEP DENSE_RANK for latest records efficiently on large tables.

1 answer• 1 view
DatabasesFind SQL Duplicates by Email & Name: GROUP BY Guide

Learn to find and remove SQL duplicates by multiple fields like email and name using GROUP BY, HAVING, window functions. Examples for detecting, retrieving full rows, and safe deletion in MySQL, PostgreSQL, SQL Server.

1 answer• 5 views