Basic SQL Quiz For School Learners!

Null is a term used to describe the absence or lack of something. In this context, "rule out" means to eliminate or exclude as a possibility. Therefore, the correct answer suggests that null is not an option or cannot be considered in the given situation.

The COUNT function can be used on both numeric as well as non-numeric data. It returns the number of rows in a specified column or expression, regardless of the data type. This makes it a versatile function that can be applied to any type of data, whether it is numeric values or non-numeric values such as strings or dates.

The given answer is correct because all the statements mentioned about the COUNT function are true. COUNT(*) returns the total number of rows in the table, COUNT(exp) returns the number of non-null values in the column, and COUNT(DISTINCT exp) returns the number of unique, non-null values in the column. Therefore, all the statements are true.

The correct answer is that the join condition for natural join is basically an equijoin of all columns with the same name. This means that when using a natural join, the join condition is automatically determined based on columns with identical names in the tables being joined. This can simplify the join process as it eliminates the need to specify the join condition explicitly. However, it also means that the join may not be as flexible or customizable as when using other types of joins.

IBM is the correct answer because they were the company that developed SQL. SQL, which stands for Structured Query Language, was developed by IBM in the 1970s as a way to manage and manipulate relational databases. It has since become the standard language for managing databases and is widely used in the industry. While other companies like Microsoft and Oracle have also contributed to the development and enhancement of SQL, IBM is credited with its initial creation.

A query refers to a request for information or data from a database or search engine. It is used to retrieve specific desired results or information that matches certain criteria or conditions. Therefore, the answer "desire results" accurately describes the purpose of a query.

Both Donald D. Chamberlin and Raymond F. Boyce designed the SQL system. This means that the correct answer is "Both A & B".

The correct answer is "You cannot insert rows with NULL values to a table." This statement is not true because it is possible to insert rows with NULL values into a table. In SQL, NULL represents a missing or unknown value, and it is allowed to be inserted into a table's columns.

SQL, which stands for Structured Query Language, appeared in 1974. It was developed by IBM researchers Donald D. Chamberlin and Raymond F. Boyce. SQL is a programming language used for managing and manipulating relational databases. It provides a standardized way to interact with databases, allowing users to create, modify, and retrieve data. The introduction of SQL revolutionized the field of database management and has since become the industry standard for working with relational databases.

The correct answer is stating that most databases do not implement the entire SQL standard because of its complexity and size. This implies that there are certain aspects or features of the SQL standard that are not implemented in most databases.