# Inverse Distribution Functions

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− | + | = Inverse Distribution Functions = | |

Defined in the SQL standard in Section 10.9 <aggregate function>, | Defined in the SQL standard in Section 10.9 <aggregate function>, | ||

inverse distribution functions open whole new vistas both of | inverse distribution functions open whole new vistas both of | ||

reporting and of implementation challenges. | reporting and of implementation challenges. | ||

+ | |||

+ | = Vistas of Reporting = | ||

+ | |||

+ | * MEDIAN! YAY! | ||

+ | * N-tiles (continuous and discrete) | ||

+ | * Many others. | ||

+ | |||

+ | = Implementation Challenges = | ||

+ | |||

+ | * Parser | ||

+ | ** Mostly done. Thanks, Atri Sharma! | ||

+ | ** WITHIN GROUP clause | ||

+ | |||

+ | * Planner/Optimizer | ||

+ | ** In progress | ||

+ | ** Really applies atop FILTER, not yet in master. | ||

+ | ** New element in ProcedureCreate | ||

+ | * Executor | ||

+ | ** New way to do aggregates: transition function now optional. |

## Revision as of 02:53, 3 June 2013

# Inverse Distribution Functions

Defined in the SQL standard in Section 10.9 <aggregate function>, inverse distribution functions open whole new vistas both of reporting and of implementation challenges.

# Vistas of Reporting

- MEDIAN! YAY!
- N-tiles (continuous and discrete)
- Many others.

# Implementation Challenges

- Parser
- Mostly done. Thanks, Atri Sharma!
- WITHIN GROUP clause

- Planner/Optimizer
- In progress
- Really applies atop FILTER, not yet in master.
- New element in ProcedureCreate

- Executor
- New way to do aggregates: transition function now optional.