SQL MCQ Questions and answers

When using the SQL INSERT statement, rows can either be inserted into a table one at a time or in groups. This means that you can insert multiple rows into a table with a single INSERT statement, making it more efficient for mass data insertion. Option C is the correct choice, while Options A, B, and D do not accurately describe the capabilities of the INSERT statement.

The SQL ALTER statement is primarily used to change the table structure. It allows you to modify the structure of an existing table by adding, modifying, or deleting columns, as well as changing various constraints or properties of the table. Option B is the correct choice, while Options A, C, and D do not accurately describe the primary purpose of the ALTER statement.

To delete columns from a table in SQL, you can use the ALTER TABLE TableName DROP COLUMN ColumnName command. Option D is the correct choice for removing columns from a table. Options A, B, and C do not represent the standard SQL syntax for deleting columns.

To add columns to a table in SQL, you can use the ALTER TABLE TableName ADD ColumnName command. Option A is the correct choice for adding new columns to an existing table. Options B, C, and D do not represent the standard SQL syntax for adding columns.

The command to remove rows from a table in SQL is DELETE FROM CUSTOMER WHERE .... Option D is the correct choice for deleting rows from the 'CUSTOMER' table based on specific conditions specified in the WHERE clause. Options A, B, and C do not represent the standard SQL syntax for removing rows.

The SQL WHERE clause is used to limit the rows of data that are returned from a query. It specifies a condition that must be met for a row to be included in the query result. The WHERE clause does not control which columns are returned; it focuses on filtering rows based on specified conditions. Option A accurately describes the purpose of the WHERE clause, while Option B is incorrect. Option C and Option D are also inaccurate in their descriptions.

The original purpose of SQL (Structured Query Language) was to specify the syntax and semantics of SQL manipulation language. SQL was designed to interact with and manipulate data stored in relational database management systems. While SQL has evolved to include data definition language (DDL) for defining data structures and other functionalities, its primary purpose was to provide a standardized language for querying and manipulating data, making Option C the most accurate choice. Options A and B are not the primary original purposes of SQL, and Option D is not entirely accurate as it combines multiple purposes of SQL.

The wildcard in a WHERE clause, often represented by the '%' symbol, is useful when an exact match is not possible in a SELECT statement. It allows for pattern matching and retrieval of rows that meet specific criteria, even when the exact values are not known. Options A and D are not correct because wildcards are not typically used in CREATE statements, and Option B does not accurately represent the primary use of wildcards in SQL, which is for pattern matching in SELECT statements.

To eliminate or delete a table from a database in SQL, you use the command DROP TABLE followed by the table name, as shown in Option A. The DROP TABLE command is used to permanently remove a table and all of its associated data and structure from the database. Options B, C, and D do not represent the correct SQL syntax for removing a table.

The SQL keyword LIKE is used with wildcards to perform pattern matching in SQL queries. It allows you to search for data that matches a specified pattern, making it a powerful tool for retrieving data that meets specific criteria. Option A, C, and D do not accurately represent the keyword used with wildcards in SQL.