"SQL reference sheet: DDL/DML, Joins, Aggregate Functions"

Day 15 of My 30-Day SQL Learning Journey Today I learned about Subqueries — queries inside queries that make SQL even more powerful! What I learned today: • A subquery is a query nested inside another SELECT, INSERT, UPDATE, or DELETE statement • Using subqueries in the WHERE clause to filter results dynamically • Writing correlated subqueries that depend on the outer query • Understanding when to use subqueries vs. joins for better performance Realization of the day: Subqueries are like building logic within logic — they make SQL smarter and more flexible for real-world analysis! #SQL #DataAnalytics #LearningJourney #30DaysChallenge #DataScience #SQLLearning

"🛠️ Your go-to SQL Cheat Sheet is here! Covering CREATE, ALTER, INSERT, SELECT, JOINs, and more – this quick reference is a lifesaver for daily queries. Perfect for brushing up skills! 📝 Save this and share your top SQL tip in the comments. Let’s network! #SQLCheatSheet #OracleSQL #DataManagement #QueryOptimization #TechTools #ProfessionalDevelopment"

💾 Just dropped into the world of SQL Began with the basics: DDL, DML, DQL commands—and it’s wild how much power lives in a few keywords: DDL – CREATE, ALTER, DROP, TRUNCATE DML – INSERT, UPDATE, DELETE DQL – SELECT, WHERE, GROUP BY, ORDER BY #SQL #DataJourney #DDLCommands#DMLCommands#DQLCommands #LearningByDoing #AnalyticsBeginner 

Mastering SQL JOINs doesn’t have to be confusing! In this visual guide, I’ve broken down INNER, LEFT, RIGHT, and FULL JOINs step by step — with real tables, queries, and outputs. Check the last slide and try the challenge question in the comments! 💬 #SQL #DataAnalysis #LearningSQL #DataCommunity

🎯 Master SQL Ranking Functions in Minutes! Ever wondered what’s the real difference between 👉 ROW_NUMBER() 👉 RANK() 👉 DENSE_RANK() These three SQL window functions look similar — but they can completely change your query results! ⚡ In this short and detailed video, I’ve explained each one with clear examples so you’ll never get confused again. 💡 🎥 Watch here → https://lnkd.in/guYUQj73 ✅ Perfect for: SQL learners & students Developers preparing for interviews Data analysts & DBAs If you find it helpful, drop a ❤️ and share it with your network — let’s make SQL simple for everyone! #SQL #DataAnalytics #Database #SQLServer #DataEngineering #LearnSQL #SQLTutorial #SQLFunctions #TechLearning #LinkedInLearning #DataCommunity Md Gayasuddin

📆Day 105 of 365 Days Did some research on how to get good at SQL and learned about the core categories: 🔹 DDL – CREATE, ALTER, DROP 🔹 DML – SELECT, INSERT, UPDATE, DELETE 🔹 DCL – GRANT, REVOKE 🔹 Practice focus areas: WHERE, ORDER BY, GROUP BY, HAVING, JOINs Also explored tips like practicing regularly, working with real datasets, and building mini projects to improve SQL skills. #365DaysOfCode #Day105 #SQL #Database #LearningJourney #PracticeMakesPerfect

🚀 Throwback to My Early SQL Learning Days… When One Index Changed Everything! In my early days of learning SQL, I wrote a simple query… And it took 18 seconds. 😩 I added ONE INDEX on the column used in the WHERE clause… Suddenly — 0.3 seconds. ⚡🔥 That’s when I truly understood: Indexes are like magic shortcuts. 📘 Without Index: SQL scans every row → slow. 📕 With Index: SQL jumps straight to the matching rows → super fast! ✨ Golden rule I learned early on: Index columns used in → ✔ WHERE ✔ JOIN ✔ ORDER BY But don’t index everything — your inserts & updates will cry 😅 A tiny tweak… massive performance boost. That moment shaped my entire approach to SQL. 💡 #SQL #DataAnalytics #Indexing #PerformanceTuning #Dataanalyst

🚀 Make your SQL queries cleaner with CTEs Messy nested subqueries? Hard to debug? That’s where CTEs (Common Table Expressions) shine. WITH high_earners AS ( SELECT name, salary FROM employee WHERE salary > 5000 ) SELECT company, COUNT(*) AS total_high_earners FROM high_earners GROUP BY company; ✅ Easier to read ✅ Easier to debug ✅ Reusable within the same query Once you start using CTEs, you’ll never go back to deeply nested subqueries. 🔎 Do you prefer CTEs or subqueries in your SQL? #SQL #DataEngineering #DataAnalytics #BusinessIntelligence #LearningSQL #TechTips

Part 3- day 2 of relearning SQL Combining two aggregate function: Count and distinct. SELECT COUNT(DISTINCT(column_name)) FROM table_name And also adding a filter clause if I want to use a condition for that query . WHERE column_name > 50 Everything is coming together now for me. SQL feels simple now for me. Going back to the basics taking it one step at a time is the secrete to understanding this tool. #SQL #tech #database #relearn #mySQLjourney

That moment when you proudly run your SQL query… and get 0 rows instead of 10,000. 😅 You check the syntax, the joins, the WHERE clause… and then realize you used = instead of LIKE. SQL doesn’t make mistakes — we do. Repeatedly. But every failed query teaches something (usually humility). What’s the smallest typo that completely broke your SQL query? #SQL #DataAnalytics #DataHumor #LearningByDoing