startTime := curMM||'01 00:00:00'; endTime := to_char( startTime::timestamp + interval '1 month', 'YYYY-MM-DD HH24:MI:SS'); strSQL := 'CREATE TABLE IF NOT EXISTS '||TG_RELNAME||'_'||curMM|| ' ( CHECK('||time_column_name||'>='''|| startTime ||''' AND ' ||...
ORDER BY month; 使用窗口函数:可以使用窗口函数ROW_NUMBER()对日期进行排序,并使用PARTITION BY子句将数据分组为每个月,然后选择每个分组中的最后一行。 代码语言:txt 复制 SELECT month, your_value_column AS last_value FROM ( SELECT date_trunc('month', your_date_column) AS month, your_value_column, ...
SUBPARTITION BY HASH(p_month) SUBPARTITIONS 2 ( partition t1_p1 values less than (to_date('2022-01-01','yyyy-MM-dd'))( SUBPARTITION t1_p1_h1, SUBPARTITION t1_p1_h2 ), partition t1_p2 values less than (to_date('2022-01-15','yyyy-MM-dd'))( SUBPARTITION t1_p2_h1, SUBPARTITION ...
CREATE TABLE split_table_mouth_test1_01 PARTITION OF split_table_mouth_test1 FOR VALUES FROM (1) TO (2); CREATE TABLE split_table_mouth_test1_02 PARTITION OF split_table_mouth_test1 FOR VALUES FROM (2) TO (3); CREATE TABLE split_table_mouth_test1_03 PARTITION OF split_table_mouth_test...
select to_char( now() + interval '1 month','YYYYMM'); --current_timestamp 同 now() 函数等效 select current_timestamp; SELECT to_char(current_timestamp, 'YYYY-MM-DD HH24:MI:SS'); --近一周 select now() - interval '1 week'; ...
RETURN year_month; END; $$ LANGUAGE plpgsql; 这个函数将 hire_date 字段的年份和月份组合成一个整数,作为分区键。 3、创建分区策略 创建一个分区策略,将分区函数与主表关联起来。 CREATE PARTITION TABLE employees PARTITION BY RANGE (partition_by_year_month()); ...
我们可以使用窗口函数内的Order by降序聚合来实现这个目标。 以下是一个示例查询,演示了如何在PostgreSQL中使用窗口函数内的Order by降序聚合: 代码语言:txt 复制 SELECT month, product, sales FROM ( SELECT month, product, sales, ROW_NUMBER() OVER (PARTITION BY month ORDER BY sales DESC) AS rank FROM ...
tablepartitionsadd_month,按月生成分区表,一月一个分区表 CREATEORREPLACEFUNCTIONpublic.tablepartitionsadd_month( p_tablenametext, p_schematext, p_date_starttext, p_stepinteger)RETURNSvoid LANGUAGE'plpgsql'COST100VOLATILE PARALLEL UNSAFEAS$BODY$declarev_cntint; ...
A common solution for this is to partition by month (or whatever granularity is desired). Then, the procedure becomes: detach the old partition, dump it for the archives, and drop the table. Now, there is nothing to vacuum at all. ...
CREATE TABLE students (id INTEGER, status character varying(30), name character varying(30)) PARTITION BY LIST(status); CREATE TABLE stu_active PARTITION OF students FOR VALUES IN ('ACTIVE'); CREATE TABLE stu_exp PARTITION OF students FOR VALUES IN ('EXPIRED'); ...