O Erro Que Faz Seu JOIN Duplicar Dados... E Quase Ninguém Percebe #sql #bancodedados

📝 VIDEO DESCRIPTION You perform a JOIN… the query runs… but the numbers start to become larger than they should be? In this video you will understand: ✅ why this happens ✅ how JOIN multiplies rows ✅ the real problem of cardinality ✅ when to use DISTINCT ✅ and how to avoid incorrect results in SQL This is one of the most treacherous SQL errors… because the query DOES NOT break. It simply returns incorrect numbers. And many people trust the result without realizing the problem. 📌 In this video you will see: ✔ JOIN multiplying records ✔ COUNT returning incorrect values ✔ Cardinality in practice ✔ Relationship between queries and exams ✔ How to correct using COUNT(DISTINCT) ✔ The reasoning behind SQL 💡 Main phrase of the video: “JOIN doesn't join tables. JOIN joins rows.” 📚 Want to practice SQL with real-world scenarios? Discover the Art of Query: 👉 https://artedaquery.com.br/ 📌 If this video helped you: 👍 leave a like 💬 comment if you've ever encountered this problem 🔔 and subscribe to the channel Because here you learn SQL clearly… not by memorizing commands. #sql #mysql #sqlserver #postgresql #database #programming #development #dataanalysis #dataanalytics #joinsql