Can we use SELECT statement in case in Oracle?

Introduction to Oracle CASE expression You can use a CASE expression in any statement or clause that accepts a valid expression. For example, you can use the CASE expression in statements such as SELECT , UPDATE , or DELETE , and in clauses like SELECT , WHERE , HAVING , and ORDDER BY .

Can we use SELECT query inside CASE statement?

The case statement in SQL returns a value on a specified condition. We can use a Case statement in select queries along with Where, Order By, and Group By clause. It can be used in the Insert statement as well.

Can we use with clause inside with clause in Oracle?

no,you can’t nest them. you can use multiple cte’s though.

Can we use CASE statement in WHERE clause?

You can use a CASE Statement anywhere a valid expression is used within the SELECT statement such as the WHERE clause’s filter criteria.

Can CASE statement return multiple values in Oracle?

A CASE statement cannot return more than one value, it is a function working on one value.

How do I fix Ora 12704 character set mismatch?

To solve this error, Strings declared with NCHAR or NCHAR VARYING do not interoperate with strings declared with CHAR or VARCHAR2. Use TRANSLATE() function to explicitly convert one to the other. You can use the conversion function ( NCHAR, VARCHAR2 ) to change the type of the two columns to be consistent.

What is a SELECT case statement?

A Select Case statement allows a variable to be tested for equality against a list of values. Each value is called a case, and the variable being switched on is checked for each select case.

How do you put two conditions in a case statement in SQL?

Here are 3 different ways to apply a case statement using SQL:

1. (1) For a single condition: CASE WHEN condition_1 THEN result_1 ELSE result_2 END AS new_field_name.
2. (2) For multiple conditions using AND: CASE WHEN condition_1 AND condition_2 THEN result_1 ELSE result_2 END AS new_field_name.

How do I write an inner select query in SQL?

SQL – Sub Queries

1. Subqueries must be enclosed within parentheses.
2. 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.
3. An ORDER BY command cannot be used in a subquery, although the main query can use an ORDER BY.

What is subquery factoring in Oracle?

Subquery factoring, also known as the WITH clause, provides a convenient and flexible way for us to define subqueries and in-line views in Oracle 9i. The primary purpose of subquery factoring is to reduce repeated table accesses by generating temporary datasets during query execution.

Can a case statement be a join?

There are plenty of ways to resolve for this: a subquery with a CASE statement in the join statement for the table you are joining in, a CASE statement in a temp table where all values are changed to match, or this handy little trick of using a CASE statement in the JOIN’s ON clause.

Can a case when statement return multiple values?

CASE by definition only returns a single value. Ever.