- Correlated and non-correlated.
Non-correlated
Correlated
The inner query doesn't depend on the outer query.
Inner query depends on the outer query.
Can run as a standalone query.
Can't run as a standalone query.
Executed only once.
Executed once for each row selected in the outer query.
Executed before the outer query.
Executed after the outer query.
Can't be used instead of JOIN on the outer query.
Can be used instead of JOIN on the outer query, but will be slower than a JOIN.
- SELECT, WHERE, FROM, INSERT, UPDATE, and DELETE clauses.
- SELECT and WHERE clauses.
- A container for a single SQL statement that will allow you to query a temporary result set.
- Recursive and non-recursive.
- Locking is what happens when a query runs against a database.
- With an index hint.
- READ UNCOMMITTED, READ COMMITTED, REPEATABLE READ...
United States
United Kingdom
India
Germany
France
Canada
Russia
Spain
Brazil
Australia
Argentina
Austria
Belgium
Bulgaria
Chile
Colombia
Cyprus
Czechia
Denmark
Ecuador
Egypt
Estonia
Finland
Greece
Hungary
Indonesia
Ireland
Italy
Japan
Latvia
Lithuania
Luxembourg
Malaysia
Malta
Mexico
Netherlands
New Zealand
Norway
Philippines
Poland
Portugal
Romania
Singapore
Slovakia
Slovenia
South Africa
South Korea
Sweden
Switzerland
Taiwan
Thailand
Turkey
Ukraine