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dev:sql:statements:partition:home [2010/07/08 23:01] tdo |
dev:sql:statements:partition:home [2016/06/28 22:38] (current) |
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===== Description ===== | ===== Description ===== | ||
- | The PARTITION statement reads a table and splits it into multiple sub partitions which can be useful when setting up an Omnidex grid. The output of the PARTITION statement is multiple files that are named as follows: table_name_<distinct_value>.dat. | + | The PARTITION statement reads a table and splits it into multiple sub partitions which can be useful when setting up an Omnidex grid. |
===== Syntax ===== | ===== Syntax ===== | ||
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[WITH options] | [WITH options] | ||
</code> | </code> | ||
+ | ===== Discussion ===== | ||
+ | |||
+ | The output of the PARTITION statement is multiple files that are named as follows: table_name_<distinct_value>.dat. | ||
- | ===== 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 partition statement is used with criteria to split a table into multiple components. | ||