This shows you the differences between two versions of the page.
|
dev:sql:statements:partition:home [2010/07/08 23:06] tdo |
dev:sql:statements:partition:home [2016/06/28 22:38] |
||
|---|---|---|---|
| Line 1: | Line 1: | ||
| - | {{page>:top_add&nofooter&noeditbtn}} | ||
| - | <html><div align="center"><span style="color:red">DRAFT</span></div></html> | ||
| - | ====== Omnidex SQL: PARTITION ====== | ||
| - | {{page>:sql_bar&nofooter&noeditbtn}} | ||
| - | ===== Description ===== | ||
| - | The PARTITION statement reads a table and splits it into multiple sub partitions which can be useful when setting up an Omnidex grid. | ||
| - | |||
| - | ===== Syntax ===== | ||
| - | <code> | ||
| - | PARTITION table_spec | ||
| - | [INTO n] | ||
| - | [BY <column_spec | expression>] | ||
| - | [IN path] | ||
| - | [ON [INSTANCE] instance_no] | ||
| - | [WITH options] | ||
| - | </code> | ||
| - | ===== Discussion ===== | ||
| - | |||
| - | |||
| - | ===== Examples ===== | ||
| - | ==== Partition by Column ==== | ||
| - | This example will partition a table into multiple sub tables for each state. Note that the filename suffix is the distinct state value. | ||
| - | <code> | ||
| - | > partition households by state ; | ||
| - | Partitioned 1,909 rows from HOUSEHOLDS into 52 partitions | ||
| - | > dir | ||
| - | HOUSEHOLDS_AK.dat | ||
| - | HOUSEHOLDS_AL.dat | ||
| - | HOUSEHOLDS_AR.dat | ||
| - | HOUSEHOLDS_AZ.dat | ||
| - | HOUSEHOLDS_CA.dat | ||
| - | HOUSEHOLDS_CO.dat | ||
| - | HOUSEHOLDS_CT.dat | ||
| - | HOUSEHOLDS_DC.dat | ||
| - | HOUSEHOLDS_DE.dat | ||
| - | HOUSEHOLDS_FL.dat | ||
| - | HOUSEHOLDS_GA.dat | ||
| - | HOUSEHOLDS_HI.dat | ||
| - | HOUSEHOLDS_IA.dat | ||
| - | HOUSEHOLDS_ID.dat | ||
| - | HOUSEHOLDS_IL.dat | ||
| - | HOUSEHOLDS_IN.dat | ||
| - | HOUSEHOLDS_KS.dat | ||
| - | HOUSEHOLDS_KY.dat | ||
| - | HOUSEHOLDS_LA.dat | ||
| - | … | ||
| - | </code> | ||
| - | ==== Partition with criteria and CASE ==== | ||
| - | The partition statement is used with criteria to split a table into multiple components. | ||
| - | |||
| - | The SQL CASE syntax can be used to specify the suffix used when the PARTITION statement creates the component files. | ||
| - | <code> | ||
| - | > partition companies by | ||
| - | "case when state in ('CA','CO','TX') then '01' | ||
| - | when state in ('NY','FL','WA') then '02' | ||
| - | else '03' end" ; | ||
| - | Partitioned 31,548 rows from COMPANIES into 3 partitions | ||
| - | </code> | ||
| - | |||
| - | {{page>:bottom_add&nofooter&noeditbtn}} | ||