Multiple choice technology databases

Sub-queries can be nested in

  1. DELETE statements only

  2. UPDATE, DELETE, INSERT and SELECT statements

  3. UPDATE statements only

  4. INSERT statements only
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

SQL subqueries are versatile and can be nested within all four major DML statements: SELECT, INSERT, UPDATE, and DELETE. This allows for complex data manipulation where the inner query's results determine which rows are affected by the outer statement. For example, you can use a subquery in an UPDATE statement to filter rows based on values from another table, or in DELETE to remove rows matching specific criteria from a subquery.

AI explanation

To answer this question, you need to understand the concept of sub-queries and where they can be nested.

Sub-queries are queries that are nested within another query. They are used to retrieve data from one or more tables and can be used in various types of SQL statements.

The correct answer is B) UPDATE, DELETE, INSERT, and SELECT statements.

Explanation for each option:

A) DELETE statements only - This option is incorrect because sub-queries can be nested in other types of statements as well, not just DELETE statements.

B) UPDATE, DELETE, INSERT, and SELECT statements - This option is correct because sub-queries can be nested in UPDATE, DELETE, INSERT, and SELECT statements. They can be used to filter or retrieve data based on conditions from other tables.

C) UPDATE statements only - This option is incorrect because sub-queries can be used in other types of statements as well, not just UPDATE statements.

D) INSERT statements only - This option is incorrect because sub-queries can be used in other types of statements as well, not just INSERT statements.

Therefore, the correct answer is B) UPDATE, DELETE, INSERT, and SELECT statements.

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