SQL Basics: DDL DML DCL TCL DQL Explained

Confused by SQL commands? You’re not alone. 👨💻 Understanding SQL isn’t about memorizing queries — it’s about knowing when to use what. Here’s the simple breakdown: 🔹 DML → Work with data (Insert, Update, Delete) 🔹 DQL → Retrieve data (Select) 🔹 DDL → Define structure (Create, Alter, Drop) 🔹 DCL → Control access (Grant, Revoke) Once you understand this, SQL becomes way easier to navigate. 💡 Tip: Focus on concepts first; syntax becomes easy after. Save this post — you’ll come back to it more than you think 🔖 📌 Which SQL command do you use the most? #SQL #LearnSQL #Database #Programming #TechSkills #CodingLife #DeveloperLife #DataAnalytics #BackendDevelopment #WebDevelopment #TechEducation #CodingTips #SoftwareDevelopment #LearnToCode #SQLTutorial #DataScienceBasics #DeveloperJourney #CodeSmart

🚀 Day 16/30 – SQL Challenge 🔹 Problem: Find the first year each product was sold along with its details. 🔹 Approach: Used MIN(year) with a JOIN to get the correct records. Also explored using ROW_NUMBER(). 🔹 Learning: Avoid tuple IN queries and prefer JOINs or window functions for better results. #SQL #LeetCode #Day16 #CodingJourney #ProblemSolving #SDE

🚀 Day 18 of Learning SQL Today I explored Subqueries in SQL and understood how powerful they are when dealing with complex conditions. Here’s what I learned: 🔹 Subqueries are queries written inside another query 🔹 They are useful when we need to find unknown values or conditions 🔹 Help in breaking complex problems into smaller, manageable parts 🔹 Commonly used with SELECT, WHERE, and FROM clauses 💡 Key Insight: Whenever we don’t know an exact value or condition beforehand, we can use a subquery to dynamically fetch it and use it in the main query. This concept made me realize how SQL can solve real-world problems efficiently by combining multiple queries. Step by step, building stronger SQL skills! 💪 #Day18 #SQL #Subqueries #LearningJourney #DataAnalytics #Programming #Database

SQL Learning Journey — Day 5 Today was all about **revision + debugging real SQL queries**  Revised concepts: • SELECT & WHERE • Aggregate functions (AVG, COUNT) • Subqueries • JOIN + GROUP BY + HAVING  Biggest learning today: Errors are the best teachers! I faced multiple issues like:  Unknown column errors  Ambiguous column names  JOIN syntax mistakes And learned how to fix them step by step.  Highlight: Wrote a query to find students enrolled in more than one course using JOIN and HAVING. Consistency > Perfection Day 5 completed #SQL #LearningInPublic #100DaysOfCode #DataAnalytics

𝗠𝘆𝗦𝗤𝗟 𝗗𝗮𝘆 𝟲 — 𝗦𝗤𝗟 𝗖𝗼𝗺𝗺𝗮𝗻𝗱𝘀 𝗮𝗻𝗱 𝗖𝗼𝗿𝗲 𝗖𝗼𝗻𝗰𝗲𝗽𝘁𝘀 🚀 Today’s session focused on how to effectively work with data using SQL 💻 𝗞𝗲𝘆 𝗖𝗼𝗺𝗺𝗮𝗻𝗱𝘀: • CREATE 🏗️ — define table structure • INSERT ➕ — add records • SELECT 🔍 — retrieve data (no modification) • UPDATE ✏️ — modify existing data • DELETE 🗑️ — remove specific rows • TRUNCATE ⚡ — remove all data quickly • DROP ❌ — delete table completely 𝗖𝗼𝗿𝗲 𝗖𝗼𝗻𝗰𝗲𝗽𝘁𝘀: • WHERE clause 🎯 for precise filtering • AND 🔗 for handling multiple conditions • Arithmetic operations ➕➖✖️➗ in queries • Difference between DELETE, TRUNCATE, DROP ⚖️ • SELECT only retrieves data, it does not alter database values ❗ 𝗦𝗤𝗟 𝗖𝗮𝘁𝗲𝗴𝗼𝗿𝗶𝗲𝘀: DDL | DML | DQL | TCL | DCL 📚 𝗥𝗲𝗮𝗹-𝘄𝗼𝗿𝗹𝗱 𝗶𝗻𝘀𝗶𝗴𝗵𝘁: Transactions using COMMIT ✅, ROLLBACK 🔄, and SAVEPOINT 📍 ensure data reliability — just like secure money transfers 💸 𝗞𝗲𝘆 𝗧𝗮𝗸𝗲𝗮𝘄𝗮𝘆: SQL is not just syntax — it’s about understanding and controlling data 🧠 #MySQL #SQL #Database #Learning #Tech #FullStack #Day6

📝 Deep Dive into SQL Fundamentals. Data is only as good as the way you manage it. I’ve been documenting the core principles of Structure Query Language (SQL)—from basic syntax to advanced database relationships. My latest notes cover: 🔹 CURD Operations (Create, Update, READ, Drop). 🔹 Relational Keys (Primary vs. Foreign). 🔹 Logical Operators for precise data retrieval. Always learning, always growing. 📈 #SoftwareEngineering #SQL #Database #Programming #Notes #LearningJourney

WHERE vs HAVING in SQL Filtering data in SQL isn't always straightforward. Knowing when to use WHERE vs HAVING can save you from incorrect results. 🔹 WHERE filters rows before aggregation 🔹 HAVING filters results after aggregation 🔹 Use WHERE for raw data filtering 🔹 Use HAVING for grouped data filtering 💡 Master this difference to write cleaner and more accurate SQL queries. Save this post for your SQL learning journey. Follow JACOB JEYAKUMAR S for more updates #SQL #SQLServer #DataAnalytics #Database #DataEngineering #Programming #TechTips

Today I learned something interesting while solving SQL problem 👇 I used ROUND() thinking it will convert integer to decimal ❌ But I realized: ROUND() only formats output, it does NOT change datatype. 👉 Example: 5 / 2 = 2 5 / 2.0 = 2.5 Small learning, but important for avoiding wrong results. #SQL #LearningDaily

Day 15 of my DSA journey — SQL Practice Today I focused on SQL and continued working on the SQL 50 study plan on LeetCode. What I covered: • SELECT queries and filtering • JOIN operations (INNER JOIN, LEFT JOIN) • Handling NULL values • GROUP BY with aggregate functions • Writing queries for real-world scenarios Progress: • Completed 23 / 50 SQL problems Key takeaway: SQL is all about understanding the data first, then applying the right operations like filtering, joining, and grouping. Thinking in terms of tables and relationships makes queries much easier to write. #DSA #SQL #LeetCode #Database #CodingJourney #Learning

Day 27/30 – SQL Challenge 🚀 Today’s challenge was all about identifying prime numbers using SQL — not something you see every day in database queries! Instead of traditional programming, I used recursive queries and logical filtering to: Generate numbers up to a limit Check divisibility conditions Filter out non-prime numbers Present results in a single line using a custom separator (&) 💡 Key takeaway: SQL isn’t just for data retrieval — with the right approach, it can handle complex logical problems too. This challenge really helped me think beyond basic queries and explore the power of recursive CTEs and conditional logic. #SQL #DataEngineering #ProblemSolving #30DaysOfSQL #LearningJourney