When.com Web Search

Search results

  1. Results From The WOW.Com Content Network
  2. Correlated subquery - Wikipedia

    en.wikipedia.org/wiki/Correlated_subquery

    Correlated subqueries may appear elsewhere besides the WHERE clause; for example, this query uses a correlated subquery in the SELECT clause to print the entire list of employees alongside the average salary for each employee's department. Again, because the subquery is correlated with a column of the outer query, it must be re-executed for ...

  3. SQL syntax - Wikipedia

    en.wikipedia.org/wiki/SQL_syntax

    A derived table is the use of referencing an SQL subquery in a FROM clause. Essentially, the derived table is a subquery that can be selected from or joined to. The derived table functionality allows the user to reference the subquery as a table. The derived table is sometimes referred to as an inline view or a subselect.

  4. Select (SQL) - Wikipedia

    en.wikipedia.org/wiki/Select_(SQL)

    A derived table is a subquery in a FROM clause. Essentially, the derived table is a subquery that can be selected from or joined to. Derived table functionality allows the user to reference the subquery as a table. The derived table also is referred to as an inline view or a select in from list.

  5. Where (SQL) - Wikipedia

    en.wikipedia.org/wiki/Where_(SQL)

    The WHERE clause is used in conjunction with SQL DML statements, and takes the following general form: SQL - DML - Statement FROM table_name WHERE predicate all rows for which the predicate in the WHERE clause is True are affected (or returned) by the SQL DML statement or query.

  6. Join (SQL) - Wikipedia

    en.wikipedia.org/wiki/Join_(SQL)

    Conversely, an inner join can result in disastrously slow performance or even a server crash when used in a large volume query in combination with database functions in an SQL Where clause. [2] [3] [4] A function in an SQL Where clause can result in the database ignoring relatively compact table indexes. The database may read and inner join the ...

  7. Delete (SQL) - Wikipedia

    en.wikipedia.org/wiki/Delete_(SQL)

    Deletes all or some records from the table, you can limit the records to be deleted by using the WHERE clause Does not free the space occupied by the data in the table (in the TABLESPACE) Does not reset the SEQUENCE value assigned to the table

  8. View (SQL) - Wikipedia

    en.wikipedia.org/wiki/View_(SQL)

    Therefore, an ORDER BY clause in the view definition is meaningless; the SQL standard does not allow an ORDER BY clause in the subquery of a CREATE VIEW command, just as it is refused in a CREATE TABLE statement.

  9. Conjunctive query - Wikipedia

    en.wikipedia.org/wiki/Conjunctive_Query

    Conjunctive queries without distinguished variables are called boolean conjunctive queries.Conjunctive queries where all variables are distinguished (and no variables are bound) are called equi-join queries, [1] because they are the equivalent, in the relational calculus, of the equi-join queries in the relational algebra (when selecting all columns of the result).