Get the first row of records for each group
In SQL, retrieving the first record of each unique grouping is a common task. Consider this situation, we have two tables, SM_Employee and SM_SalesRepWorkflow. By combining these two tables, we want to select the first row of information from SM_SalesRepWorkflow for each sales representative for the current month and year, sorted by SalesRepId.
To achieve this, we can take advantage of the functionality of the ROW_NUMBER() function. Here is a detailed explanation of the query:
SELECT * FROM( SELECT workflowid, salesRepId, quantityAssigned, quantityLeft, month, year, ROW_NUMBER() OVER (PARTITION BY salesRepId ORDER BY workflowid) AS rownumber FROM sm_salesRepWorkflow ) WHERE rownumber = 1;
- The subquery calculates the row number for each sales representative based on salesRepId and sorts by workflowid in ascending order.
- The main query then filters the subquery to only include rows with rownumber 1, ensuring we retrieve the first row for each salesRepId.
By using the ROW_NUMBER() function, we can efficiently select the initial record for each sales representative while adhering to the specified conditions. This technique is useful in various scenarios where you need to group and select the first row of each group.
The above is the detailed content of How to Select the First Row of Each Group in SQL Using ROW_NUMBER()?. For more information, please follow other related articles on the PHP Chinese website!

This article explores optimizing MySQL memory usage in Docker. It discusses monitoring techniques (Docker stats, Performance Schema, external tools) and configuration strategies. These include Docker memory limits, swapping, and cgroups, alongside

This article addresses MySQL's "unable to open shared library" error. The issue stems from MySQL's inability to locate necessary shared libraries (.so/.dll files). Solutions involve verifying library installation via the system's package m

The article discusses using MySQL's ALTER TABLE statement to modify tables, including adding/dropping columns, renaming tables/columns, and changing column data types.

This article compares installing MySQL on Linux directly versus using Podman containers, with/without phpMyAdmin. It details installation steps for each method, emphasizing Podman's advantages in isolation, portability, and reproducibility, but also

This article provides a comprehensive overview of SQLite, a self-contained, serverless relational database. It details SQLite's advantages (simplicity, portability, ease of use) and disadvantages (concurrency limitations, scalability challenges). C

This guide demonstrates installing and managing multiple MySQL versions on macOS using Homebrew. It emphasizes using Homebrew to isolate installations, preventing conflicts. The article details installation, starting/stopping services, and best pra

Article discusses configuring SSL/TLS encryption for MySQL, including certificate generation and verification. Main issue is using self-signed certificates' security implications.[Character count: 159]

Article discusses popular MySQL GUI tools like MySQL Workbench and phpMyAdmin, comparing their features and suitability for beginners and advanced users.[159 characters]


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

AI Hentai Generator
Generate AI Hentai for free.

Hot Article

Hot Tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

Dreamweaver CS6
Visual web development tools

ZendStudio 13.5.1 Mac
Powerful PHP integrated development environment

Safe Exam Browser
Safe Exam Browser is a secure browser environment for taking online exams securely. This software turns any computer into a secure workstation. It controls access to any utility and prevents students from using unauthorized resources.

PhpStorm Mac version
The latest (2018.2.1) professional PHP integrated development tool
