ALTER TABLE SALES MERGE PARTITIONS P1,P2 INTO PARTITION P2 UPDATE INDEXES; --如果省略update indexes子句的话,必须重建受影响的分区的index; ALTER TABLE range_example MODIFY PARTITION part02 REBUILD UNUSABLE LOCAL INDEXES; 实例: ALTER TABLE table_name1 MERGE PARTITIONS TICKET_GSMNEAR_201604 , TICKET_G...
PARTITION BY 类似于 GROUP BY 的语义, 专用于窗口的分组 ORDER BY 窗内的排序依据, 依据的字段决定了 RANGE 的类型 RANGE ... PRECEDING 在当前值之前的范围, 基准是当前记录这个 ORDER BY 字段的值 RANGE ... FOLLOWING 在当前值之后的范围, 基准是当前记录这个 ORDER BY 字段的值 RANGE BETWEEN ... PRE...
PARTITION BY 类似于 GROUP BY 的语义, 专用于窗口的分组 ORDER BY 窗内的排序依据, 依据的字段决定了 RANGE 的类型 RANGE ... PRECEDING 在当前值之前的范围, 基准是当前记录这个 ORDER BY 字段的值 RANGE ... FOLLOWING 在当前值之后的范围, 基准是当前记录这个 ORDER BY 字段的值 RANGE BETWEEN ... PRE...
One of the most critical design decisions will be the column or columns by which you partition your data.Often the best choice will be to partition by the column or set of columns which most commonly appear in WHERE clauses of queries being executed on the partitioned table. WHERE clauses ...
When to Partition a Table什么时候需要分区表,官网的2个建议如下: Tables greater than 2GB should always be considered for partitioning. Tables containing historical data, in which new data is added into the newest partition. A typical example is a historical table where only the current month's da...
partition by 指定分区表的类型range或list 指定分区列,或表达式作为分区键。 range分区表键:支持指定多列、或多表达式,支持混合(键,非表达式中的列,会自动添加not null的约束) list分区表键:支持单个列、或单个表达式 分区键必须有对应的btree索引方法的ops(可以查看系统表得到) ...
PostgreSQL是一种开源的关系型数据库管理系统,它支持高度可扩展的数据存储和处理能力。在计算多行之间的差异方面,PostgreSQL提供了多种方法和功能。 使用窗口函数:PostgreSQL支持窗口函数,可以在查询结果中计算多行之间的差异。窗口函数可以通过PARTITION BY子句将数据分组,并使用ORDER BY子句对数据进行排序。然后,可以使用LA...
This example uses the NTILE() function to divide rows in the sales_stats table into two partitions and 3 buckets for each: SELECT name, amount, NTILE(3) OVER( PARTITION BY year ORDER BY amount ) FROM sales_stats; Here is the result set: In this tutorial, you have learned how to use...
-- our new table, same structure as the example in-- the previous sectionCREATETABLEgithub_columnar_events(LIKEgithub_events)PARTITIONBYRANGE(created_at);-- create partitions to hold two hours of data eachSELECTcreate_time_partitions(table_name:='github_columnar_events',partition_interval:='2 ho...
pg_add_partition_table.py 文件:其中 create_table函数是创建子表SQL。其中参数参数名 含义db 指向数据库table 主表sub_table 正要新建的子表名start_date 范围分界开始值end_date 范围分界结束值#!/usr/bin/python3import psycopg2from config import config# example: create table tbl_game_android_step_log_...