psql中set，\set和\pset之间的区别 [英] Difference between set, \set and \pset in psql

问题描述

使用 psql 和何时使用设置和<$时，我有时会感到困惑c $ c> \set 与 \pset 的对比。我认为：

I get a little confused some times when working with psql between when to use a set vs. \set vs. \pset. I think that:

• set 是用于连接数据库的会话变量。例如 SET ROLE dba ;


• \set 用于局部变量对于此psql会话。例如 \设置时间'select current_timestamp'


• \pset 用于此psql会话的psql设置。例如'\pset border 2'

• set is for session variables on my connection to the db. For example SET ROLE dba;
• \set is for local variables for this psql session. For example \set time 'select current_timestamp'
• \pset is for psql settings for this psql session. For example '\pset border 2'

但是，我已经从来没有发现我认为这是一个很好的解释。我的上述假设正确吗？

But, I've never found what I thought was a good explanation of each. Are my assumptions above correct?

我正在使用PostgreSQL 9.4

I'm using PostgreSQL 9.4

推荐答案

基本正确。重要的区别是 SET 是SQL命令，而其他两个是psql元命令-由前缀 \ 。

Basically correct. The important difference is that SET is an SQL command while the other two are psql meta-commands - indicated by the prefixed \.

• SET 是用于更改运行时参数的SQL命令。它在服务器上执行，与psql本身无关。

• SET is an SQL command to change run-time parameters. It is executed on the server and has nothing to do with psql per se.

\set 是一个psql元命令，每个文档：

\set is a psql meta-command and, per documentation:

将psql变量名称设置为[...]

Sets the psql variable name to value [...]

该命令与SQL命令 SET 无关。

Note: This command is unrelated to the SQL command SET.

\pset 是另一个psql元命令。 每个文档：

\pset is another psql meta-command. Per documentation:

此命令设置影响查询结果表输出的选项

This command sets options affecting the output of query result tables

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