PostgreSQL中的currval函数抱怨“列不存在”。

问题描述

我正在尝试使用PostgreSQL的 currval 函数返回名为 Concept 的表的最后插入的行ID。 Concept 有一个名为 cid 的串行主键，并且有一个自动生成的名为 Concept_cid_seq 。

I am trying to use PostgreSQL's currval function to return the last inserted row id of a table called Concept. Concept has a serial primary key called cid and there was an automatically generated Sequence called Concept_cid_seq.

我尝试以下语句并得到错误：

I try the following statement and get an error:

SELECT currval("Concept_cid_seq");
ERROR:  column "Concept_cid_seq" does not exist
LINE 1: SELECT currval("Concept_cid_seq");
                       ^

********** Error **********

ERROR: column "Concept_cid_seq" does not exist
SQL state: 42703
Character: 16

但是当我运行查询：

SELECT * from "Concept_cid_seq";

我得到一张表，其中有一行（正如我期望的那样），其中显示诸如last_value，start_value，等等...

I get a table with one row (as I'd expect) showing columns like last_value, start_value, etc...

我在这里想念什么？我是否将错误的信息传递给currval？为什么说列不存在？

What am I missing here? Am I passing the wrong information to currval? Why does it say the 'column does not exist?'

推荐答案

事实证明，这是大写和引号引起的问题。因为我想保留关系名称的大写字母，所以我需要使用 both 单引号和双引号，以便将正确的关系名称传递给 currval 。

It turns out that this was an issue with capitalization and quotes. Because I wanted to preserve the capitalization of the relation name I needed to use both single and double quotes in order to pass the correct relation name to currval.

我将查询更改为 SELECT currval（' Concept_cid_seq'）; （请注意外部单引号）并且可以正常工作。

I changed the query to SELECT currval('"Concept_cid_seq"'); (note the outer single quotes) and it worked correctly.

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