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window functions

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DataFunSummit
DataFunSummit
Jan 9, 2025 · Big Data

Spark SQL Window Function Optimizations: Concepts, Techniques, and Q&A

This article explains Spark SQL's window function fundamentals, introduces two key optimizations—Offset Window Frame and Infer Window Group Limit—and provides a detailed Q&A covering implementation details, execution plan impacts, and underlying architecture.

Apache SparkBig DataOptimization
0 likes · 13 min read
Spark SQL Window Function Optimizations: Concepts, Techniques, and Q&A
Code Ape Tech Column
Code Ape Tech Column
Jul 5, 2024 · Databases

10 Essential Intermediate to Advanced SQL Concepts

This article presents ten crucial intermediate‑to‑advanced SQL concepts—including CTEs, recursive queries, temporary functions, CASE pivots, EXCEPT vs NOT IN, self‑joins, ranking functions, delta calculations, cumulative totals, and date‑time manipulation—each explained with clear examples and code snippets.

Data PivotRankingRecursive Queries
0 likes · 11 min read
10 Essential Intermediate to Advanced SQL Concepts
Top Architect
Top Architect
Apr 2, 2024 · Databases

Ten Advanced SQL Concepts Every Data‑Science Interview Candidate Should Master

This article explains ten advanced SQL techniques—including common table expressions, recursive CTEs, temporary functions, CASE‑WHEN pivots, EXCEPT vs NOT IN, self‑joins, ranking functions, delta calculations, cumulative sums, and date‑time manipulation—providing clear explanations and complete query examples to help readers ace data‑science interview questions.

Data Science InterviewsDatabaseSQL
0 likes · 14 min read
Ten Advanced SQL Concepts Every Data‑Science Interview Candidate Should Master
IT Services Circle
IT Services Circle
Jul 16, 2023 · Databases

Using MySQL Window Functions for Ranking, Aggregation, and Data Analysis

This article explains how MySQL 8.x window functions such as OVER, PARTITION BY, and ORDER BY can simplify complex ranking and aggregation queries, demonstrates creating a sample scores table, and provides practical examples of functions like ROW_NUMBER, RANK, DENSE_RANK, NTILE, LAG, and LEAD with their results.

AggregationMySQLOVER
0 likes · 18 min read
Using MySQL Window Functions for Ranking, Aggregation, and Data Analysis
Top Architect
Top Architect
Dec 7, 2022 · Databases

Ranking Student Scores with MySQL: Table Setup, User Variables, and Window Functions

This article demonstrates how to create a score table in MySQL, insert sample data, and implement ranking of students using both user‑defined variables for pre‑8.0 versions and modern window functions like RANK(), DENSE_RANK() and ROW_NUMBER() to handle ties and gaps.

DatabaseMySQLRanking
0 likes · 7 min read
Ranking Student Scores with MySQL: Table Setup, User Variables, and Window Functions
GuanYuan Data Tech Team
GuanYuan Data Tech Team
Aug 18, 2022 · Big Data

Why Spark’s compatiblePartitions Causes CPU Spikes and How to Fix It

The article investigates a Spark driver CPU overload caused by the compatiblePartitions method’s expensive permutation logic in window functions, explains the underlying O(n!) complexity, and presents a simplified implementation that eliminates the issue and has been merged into the official Spark codebase.

Big DataCPU optimizationSpark
0 likes · 7 min read
Why Spark’s compatiblePartitions Causes CPU Spikes and How to Fix It
Top Architect
Top Architect
Jul 21, 2022 · Databases

Overview of SQLite’s New SQL Features in 2018 (Versions 3.22.0–3.26.0)

The article explains SQLite’s 2018 enhancements—including boolean literals, window functions, FILTER clause, UPSERT syntax, and column‑renaming—detailing how these features work, their syntax, limitations, and providing code examples for developers seeking to use SQLite in production environments.

Database FeaturesFILTER ClauseSQL
0 likes · 10 min read
Overview of SQLite’s New SQL Features in 2018 (Versions 3.22.0–3.26.0)
Python Programming Learning Circle
Python Programming Learning Circle
Jul 20, 2022 · Databases

10 Essential SQL Concepts for Interview Preparation

This article presents ten core SQL techniques—including CTEs, recursive CTEs, temporary functions, CASE WHEN pivots, EXCEPT vs NOT IN, self‑joins, ranking window functions, delta calculations, cumulative sums, and date‑time manipulation—each explained with clear descriptions and practical query examples to help candidates ace data‑analysis interviews.

RankingSQLcase-when
0 likes · 11 min read
10 Essential SQL Concepts for Interview Preparation
Selected Java Interview Questions
Selected Java Interview Questions
Jul 15, 2022 · Databases

New SQLite SQL Features Introduced in 2018 (Versions 3.22.0–3.26.0)

The article reviews SQLite's 2018 enhancements—including boolean literals, window functions, FILTER clause, UPSERT syntax, and column‑renaming—explaining their syntax, behavior with NULLs, and practical examples, while also noting SQLite's reliability and deployment advantages despite lacking a network layer.

Boolean LiteralsDatabaseFILTER Clause
0 likes · 10 min read
New SQLite SQL Features Introduced in 2018 (Versions 3.22.0–3.26.0)
Laravel Tech Community
Laravel Tech Community
Apr 11, 2022 · Databases

Three Methods for SQL Deduplication: DISTINCT, GROUP BY, and ROW_NUMBER

This article explains three common SQL deduplication techniques—using DISTINCT, GROUP BY, and the ROW_NUMBER window function—illustrating their syntax, performance considerations, and example queries for counting unique task identifiers in relational databases.

DISTINCTGROUP BYROW_NUMBER
0 likes · 4 min read
Three Methods for SQL Deduplication: DISTINCT, GROUP BY, and ROW_NUMBER
Aikesheng Open Source Community
Aikesheng Open Source Community
Mar 23, 2022 · Databases

Using MySQL 8.0 Window Functions: first_value, last_value, nth_value, and ntile

This article explains the usage of four MySQL 8.0 window functions—first_value, last_value, nth_value, and ntile—by describing their purpose, the required window frame syntax, and providing concrete SQL examples with sample data.

MySQLSQLfirst_value
0 likes · 8 min read
Using MySQL 8.0 Window Functions: first_value, last_value, nth_value, and ntile
Laravel Tech Community
Laravel Tech Community
Nov 11, 2021 · Databases

Using DISTINCT, GROUP BY, and ROW_NUMBER for De‑duplication in SQL

This article explains how to remove duplicate rows in SQL by using DISTINCT, GROUP BY, and the ROW_NUMBER window function, compares their syntax and performance, and provides concrete examples with a Task table and a Test helper table.

DISTINCTGROUP BYROW_NUMBER
0 likes · 4 min read
Using DISTINCT, GROUP BY, and ROW_NUMBER for De‑duplication in SQL
IT Xianyu
IT Xianyu
Aug 17, 2021 · Databases

Key New Features of MySQL 8.0 for Relational Databases

MySQL 8.0 introduces several relational‑database enhancements, including invisible indexes for performance tuning, persistent configuration via SET PERSIST, default utf8mb4 character set, support for Common Table Expressions, and window functions, each illustrated with practical SQL examples.

8.0DatabaseIndexes
0 likes · 7 min read
Key New Features of MySQL 8.0 for Relational Databases
DataFunTalk
DataFunTalk
Feb 7, 2021 · Big Data

Optimizations and Extensions for Flink SQL in Tencent Real‑Time Computing Platform

This article, presented by Tencent senior engineer Du Li, details the current state of Flink SQL, compares Jar, Canvas, and SQL modes, introduces window‑function extensions, retract‑stream optimizations, and outlines future roadmap plans for cost‑based optimization and new features in the real‑time computing platform.

Big DataFlinkRetract Stream
0 likes · 19 min read
Optimizations and Extensions for Flink SQL in Tencent Real‑Time Computing Platform
Aikesheng Open Source Community
Aikesheng Open Source Community
Jan 25, 2021 · Databases

Understanding the FRAME Clause in MySQL 8.0 Window Functions

This article explains MySQL 8.0 window function FRAME clause syntax, differentiates ROWS and RANGE units, and demonstrates various frame boundaries such as CURRENT ROW, UNBOUNDED PRECEDING/FOLLOWING, and expression‑based preceding/following with concrete query examples.

DatabaseFRAME ClauseMySQL
0 likes · 10 min read
Understanding the FRAME Clause in MySQL 8.0 Window Functions
Practical DevOps Architecture
Practical DevOps Architecture
Jan 4, 2021 · Databases

New MySQL 8 Features: Invisible Indexes, Persistent Settings, UTF8MB4, CTEs, and Window Functions

This article introduces several MySQL 8 enhancements—including invisible indexes for performance testing, the SET PERSIST command for durable configuration changes, default UTF8MB4 encoding, Common Table Expressions for clearer queries, and window functions for ranking and aggregation—illustrated with practical SQL examples.

IndexesMySQLPersistent Settings
0 likes · 6 min read
New MySQL 8 Features: Invisible Indexes, Persistent Settings, UTF8MB4, CTEs, and Window Functions
Architecture Digest
Architecture Digest
Oct 11, 2020 · Databases

Understanding the Execution Order of SQL Queries

This article explains why SQL queries do not start with SELECT, outlines the typical logical execution order of clauses such as FROM, WHERE, GROUP BY, HAVING, SELECT, ORDER BY, and LIMIT, and discusses how database engines may reorder operations for optimization, with code examples and comparisons to LINQ and pandas.

LINQOptimizationSQL
0 likes · 6 min read
Understanding the Execution Order of SQL Queries
Aikesheng Open Source Community
Aikesheng Open Source Community
Oct 10, 2020 · Databases

Understanding MySQL 8.0 Window Functions: Concepts, Examples, and Use Cases

This article explains MySQL 8.0 window functions, provides clear definitions, demonstrates basic and advanced usage with sample tables and SQL queries, and lists all available window functions, helping readers apply ranking and cumulative calculations in real‑world database scenarios.

DatabaseMySQLSQL
0 likes · 8 min read
Understanding MySQL 8.0 Window Functions: Concepts, Examples, and Use Cases