6.1

The Subquery In a SELECT Statement

The Subquery in a SELECT Statement

  • A subquery is a SELECT statement coded within another SELECT statement.
  • A subquery can return a single value or a list of values.
  • A subquery can return multiple columns.
  • A subquery cannot make use of the ORDER BY clause
  • A subquery can be nested within another subquery
  • You can use a subquery in a WHERE, HAVING, FROM and SELECT clause.

Code Sample:

1    USE world;
2    SELECT name, population 
3    FROM city 
4    WHERE CountryCode IN 
5        (SELECT code 
6        FROM country 
7        WHERE region = 'Caribbean') 
8    ORDER BY population 
9    LIMIT 5;

Results:

sub_01.png

SELECT name, population

FROM city

WHERE CountryCode IN

(SELECT code

 FROM country

 WHERE region = 'Caribbean')

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