Test: SQL - Computer Science Engineering (CSE) MCQ

COUNT(*) takes null value row in to consideration.

The SQL DELETE Query is used to delete the existing records from a table.

Data definition language (DDL) commands enable you to perform the following tasks:Create, alter, and drop schema objects.

SQL commands can be used not only for searching the database but also to perform various other functions.They are DDL,DML,TCL and DCL.

SQL Aliases are defined for columns and tables. Basically aliases are created to make the column selected more readable.

SQL is a programming language used for managing data in a relational database management system. It is pronounced as See-Qwell.

DDL commands are used to define the structure of the database, table, schemas, etc. It enables us to perform the operations like CREATE, DROP, ALTER, RENAME, and TRUNCATE schema objects.
An UPDATE command is used for managing the data stored in a database. It is an example of a DML command that also includes the INSERT and DELETE commands.

TRUNCATE statement removes all rows in a table without logging the individual row deletions. It uses fewer system and transaction log resources, which makes its execution fast. This statement is similar to the DELETE statement without the WHERE clause.

The primary key can consist of a single or combination of the field that uniquely identifies each record in a table. It cannot be null or empty. A table may have duplicate columns, but it can contain only one primary key.

Constraint specifies the rule to allow or restrict what data will be stored in a table. The PRIMARY KEY, NOT NULL, and CHECK are the constraints that specify rules for data insertion.
UNION is an operator that combines two or more results from multiple SELECT queries into a single result set.