How many rows can a subquery return?

one row
A subquery is designed to find information you don’t know so that you can find information you want to know. However, single-row subqueries can return only one row. What if you need to find information based on several rows and several values? The subquery will need to return several rows.

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Which operator can be used with multiple row subqueries?

Answer: B. Multiple-row subqueries return more than one row of results. Operators that can be used with multiple-row subqueries include IN, ALL, ANY, and EXISTS. The multi row operators IN, ANY, ALL must be used with single row operators as shown in the option B.

Does exist SQL?

The EXISTS condition in SQL is used to check whether the result of a correlated nested query is empty (contains no tuples) or not. The result of EXISTS is a boolean value True or False. It can be used in a SELECT, UPDATE, INSERT or DELETE statement.

What is inner query?

A Subquery or Inner query or a Nested query is a query within another SQL query and embedded within the WHERE clause. A subquery is used to return data that will be used in the main query as a condition to further restrict the data to be retrieved.

Which of the following are the types of subqueries?

Types of SQL Subqueries

Single Row Subquery. Returns zero or one row in results.
Multiple Row Subquery. Returns one or more rows in results.
Multiple Column Subqueries. Returns one or more columns.
Correlated Subqueries.
Nested Subqueries.

What is the correct subquery?

Subqueries must be enclosed within parentheses. A subquery can have only one column in the SELECT clause, unless multiple columns are in the main query for the subquery to compare its selected columns. An ORDER BY cannot be used in a subquery, although the main query can use an ORDER BY.

How do I stop Ora 01427?

The first is to rewrite the query so that the subquery will only return a single row, thus eliminating the source of the error. This will require a user to rethink how they wish to acquire the data that they were initially searching for.

What are SQL subqueries?

A subquery is a query that is nested inside a SELECT , INSERT , UPDATE , or DELETE statement, or inside another subquery.

What is Oracle subquery?

In Oracle, a subquery is a query within a query. You can create subqueries within your SQL statements. These subqueries can reside in the WHERE clause, the FROM clause, or the SELECT clause.