SQL constraints

How to use SQL Check Constraints

Constraints in SQL Server: SQL NOT NULL, UNIQUE and SQL PRIMARY KEY

Crash course on SQL constraints! What do you want to see next? #dataanalyst #dataanalysis #dataanalytics #data #analyst #sql #coding #programming #sqlcode #techjobs #breakintotech | Mary The Analyst

💡 SQL Interview Question: 👉 How do you add a PRIMARY KEY constraint to an existing table in SQL? This is a frequently asked SQL interview question to test your understanding of constraints and table modification. Here’s the clean SQL query 👇 ALTER TABLE employees ADD CONSTRAINT pk_employees PRIMARY KEY (employee_id); 🎯 Explanation: ALTER TABLE is used to modify an existing table ADD CONSTRAINT defines a new table constraint pk_employees is the name of the primary key constraint employee_id b