SQL Server Part4 - Advance Level

SQL Server Part4 - Advance Level free download

DML, DDL queries and SQL frequently asked Interview questions - Advance level

What will you learn: Frequently asked Interview Questions with solutions + DDL | DML SQL with full explanation.

• SQL is broadly categorized into DDL (Data Definition Language) and DML (Data Manipulation Language).

• DDL is used to define and modify structures like databases, schemas, and tables.

• Commands like CREATE, DROP, ALTER, and RENAME are all part of DDL.

• DML is used for manipulating data inside tables—using SELECT, INSERT, UPDATE, and DELETE.

• A database is a structured container where all schemas, tables, and other objects are stored.

• A schema is like a folder inside a database that helps logically organize related database objects.

• A table is a set of rows and columns designed to store actual data records.

• Every table must have column names, data types, and optional constraints like PRIMARY KEY, NOT NULL, or UNIQUE.

• Use CREATE TABLE to build new tables and DROP TABLE to delete them permanently.

• Avoid using spaces and reserved keywords in table or column names; use consistent naming conventions.

• One project focused on Update_SQL_CustomerTable_ShowDiscount, updating customers’ discount values dynamically.

• Another project updated customer order quantities based on recent sales or category.

• We used SP_RENAME to rename columns—ensuring backward compatibility without losing data.

• We practiced solving real SQL interview questions that appear commonly in job scenarios.

• How to find the 4th highest ID in a table using subqueries or ROW_NUMBER().

• How to retrieve the Nth highest ID, customizable using dynamic ranking logic.

• How to identify employees who entered twice consecutively using LAG() or self-joins.

• Find customers who appeared at least three times consecutively, showing repeat behaviors.

• Write queries to count employees who got more incentives than their managers using joins.