SELECT * FROM table_name WHERE column_name = ANY(SELECT column_name FROM another_table); 复制代码 ANY关键词也可以用于数组操作中,用于判断数组中的任意一个元素是否满足条件。示例如下: SELECT * FROM table_name WHERE value = ANY('{value1, value2, value3}'); 复制代码 总的来说,ANY关键词提供...
lag(value any [, offset integer [, default any]] ) 返回偏移量值 offset integer 是偏移值,正数时取前值,负数时取后值,没有取到值时用 default 代替。 postgres=# select lag(amount,1,null) over(partition by begincity order by id),* from bills; lag | id | goodsdesc | beginunit | begi...
nth_value()窗口函数用来取结果集每一个分组的指定行 数据的字段值,语法如下所示: nth_value(value any, nth integer) 其中: value指定表的字段。 nth指定结果集分组数据中的第几行,如果不存在则返回空。例如score表按课程分组后取分组的第二行的分数,如下所示: mydb=> SELECT nth_value(score,2) OVER( ...
函数:quote_literal(value anyelement) 说明:Coerce the given value to text and then quote it as a literal. Embedded single-quotes and backslashes are properly doubled. 将一数值转换为字符串,并为其两边加上单引号,如果数值中间出现了单引号,也会被表示成两个单引号 例子:quote_literal(42.5) = '42.5...
As with any server daemon that is accessible to the outside world, it is advisable to run PostgreSQL under a separate user account. This user account should only own the data that is managed by the server, and should not be shared with other daemons. (For example, using the usernobody...
C++ typedef struct LOCALLOCK { /* tag */ LOCALLOCKTAG tag; /* unique identifier of locallock entry */ /* data */ uint32 hashcode; /* copy of LOCKTAG's hash value */ LOCK *lock; /* associated LOCK object, if any */ PROCLOCK *proclock; /* associated PROCLOCK object, if any */...
*/ switch (datum->dtype) { case PLPGSQL_DTYPE_VAR: { PLpgSQL_var *var = (PLpgSQL_var *) datum; /* * Free any old value, in case re-entering block, and * initialize to NULL */ assign_simple_var(estate, var, (Datum) 0, true, false); if (var->default_val == NULL) { /*...
/** This struct of function pointers defines the API between smgr.c and* any individual storage manager module. Note that smgr subfunctions are* generally expected to report problems via elog(ERROR). An exception is* that smgr_unlink should use elog(WARNING), rather than erroring out,* becau...
self.dcs.set_config_value(json.dumps(self.patroni.config.dynamic_configuration, separators=(',', ':'))) self.cluster = self.dcs.get_cluster() 集群初始化检测,主要检测2个方面的信息:●集群当前存在leader节点,但xxx-config中的不存在,此时,需要将leader节点上PostgreSQL的sysid设置到xxx-config中;●集...
merge_range_partitions(partitions REGCLASS[]) split_range_partition(partition REGCLASS, split_value ANYELEMENT, partition_name TEXT DEFAULT NULL) 如果是PostgreSQL 10+,则可以使用SQL语法来绑定和解绑分区,结合订阅,DDL事务功能,可以实现在线合并、分裂分区。 https://www.postgresql.org/docs/devel/static/sql...