Tag: sql

To extract data from a database using SQL, the correct option is D. SELECT.

Explanation:

The SELECT statement is used to extract or retrieve data from a database. It is one of the most commonly used SQL statements and forms the core of most database queries. The SELECT statement is followed by the columns or fields that need to be retrieved from the table or tables specified in the FROM clause. The WHERE clause can be used to filter the results based on specific conditions.

Let's go through each option and explain why it is right or wrong:

A. GET: This option is not a valid SQL statement. GET is not a SQL keyword and is not used to extract data from a database.

B. OPEN: This option is not used to extract data from a database. OPEN is used to open a cursor variable, which can then be used to fetch data from a result set.

C. EXTRACT: This option is used to extract parts of a date or time value such as year, month, day, hour, minute, or second. It is not used to extract data from a database table.

D. SELECT: This option is the correct answer. The SELECT statement is used to extract or retrieve data from a database.

E. QUERY: This option is not a specific SQL statement. Query is a general term used to refer to any SQL statement that retrieves data from a database. However, it is not a specific SQL keyword used to extract data.

Therefore, the answer is:

The Answer is: D. SELECT

To solve this question, the user needs to have a basic understanding of SQL and the syntax used to select specific columns from a table. In SQL, the SELECT statement is used to retrieve data from a database. The user must know how to specify the column name and the table name in the SELECT statement to retrieve the desired data.

Now, let's go through each option and explain why it is right or wrong:

A. EXTRACT FirstName FROM Persons: This option is incorrect. The EXTRACT keyword is used to retrieve date and time information from a specified value, not to select specific columns from a table.

B. SELECT FirstName FROM Persons: This option is correct. The SELECT statement followed by the column name (FirstName) and the table name (Persons) retrieves the data from the specified column in the specified table.

C. SELECT Persons.FirstName: This option is also correct. The SELECT statement can be written in the format of "SELECT TableName.ColumnName" to specify the table name and column name. In this case, the column name (FirstName) is preceded by the table name (Persons) and separated by a dot (.) to retrieve the desired data.

The Answer is: B