We hope you enjoyed solving the SQL exercises and learned something new along the way. Stay tuned for our next post, where we’ll bring you even more challenging SQL query questions to sharpen your proficiency. We use PostgreSQL, which is free and open source. PostgreSQL is used by some of the world's largest companies. Its SQL syntax adheres closely to the ANSI SQL standard, and the concepts you learn will apply to most database management systems, including MySQL, Oracle, SQLite, and others. Note that Microsoft SQL Server employs a variant of SQL called T-SQL, which is not covered by Practical SQL. What's In This Repository?

DELIMITER ; /* Reset the delimiter */ 40. How to create empty tables with the same structure as another table?

A sequence is a schema-bound, user-defined object which aids to generate a sequence of integers. This is most commonly used to generate values to identity columns in a table. We can create a sequence by using the CREATE SEQUENCE statement as shown below: CREATE SEQUENCE serial_num START 100; Relationships: Relations or links between entities that have something to do with each other. For example - The employee's table in a company's database can be associated with the salary table in the same database. 24. List the different types of relationships in SQL. Clustered index is used for easy and speedy retrieval of data from the database, whereas, fetching records from the non-clustered index is relatively slower. Unbelievable as it may seem, this story is true. This woman came from a very underprivileged Southeast Asian nation, and the opportunity to practice her computer skills simply had never arisen during her six long years as a computer science student.

The required query is: Select * from Worker where FIRST_NAME like '%a'; Q-18. Write an SQL query to print details of the Workers whose FIRST_NAME ends with ‘h’ and contains six alphabets. This can be done by using the DROP DATABASE command as shown in the syntax below: DROP DATABASE database_name; Consistency: This ensures that updates made to the database is valid and follows rules and restrictions. Learning SQL doesn’t have to be dry and complicated. Practical SQL delivers clear examples with an easy-to-follow approach to teach you the tools you need to build and manage your own databases.OLTP stands for Online Transaction Processing, is a class of software applications capable of supporting transaction-oriented programs. An important attribute of an OLTP system is its ability to maintain concurrency. OLTP systems often follow a decentralized architecture to avoid single points of failure. These systems are generally designed for a large audience of end-users who conduct short transactions. Queries involved in such databases are generally simple, need fast response times, and return relatively few records. A number of transactions per second acts as an effective measure for such systems. What is the main disadvantage of deleting data from an existing table using the DROP TABLE command?