The Art of SQL

Index

[SYMBOL] [A] [B] [C] [D] [E] [F] [G] [H] [I] [J] [K] [L] [M] [N] [O] [P] [Q] [R] [S] [T] [U] [V] [W] [X]

uncorrelated subqueries 2nd

     in classic style or in from clause

     not in ( ), using with

     rewriting as a join in an inline view

     rewriting as inline views in from clause

     sensitivity of operations to data volume increase

     testing for existence without other search criteria

union operator

     querying large quantities of data

unions

     of complex joins

     of intermediate result sets

     overhead of querying large union view

     partitioned tables

uniqueness, enforcement of 2nd

unnecessary coding, avoiding

unpivot operator

update statement, returning ... into ... clause

updates

     against a database

     combining multiple into one

    concurrent

         foreign key indexing

     costly massive updates

     locking and scalability

     making as fast as possible

     multiple massive updates to a table

     optimistic concurrency control

     ranking in terms of overall cost

useless queries

user-defined functions 2nd

users

     not complaining about performance

     number of, concurrency and

     perception of performance improvement