为什么psql无法识别我的单引号？ [英] Why does psql not recognise my single quotes?

问题描述

$ psql -E --host=xxx --port=yyy --username=chi --dbname=C_DB -c 'DELETE FROM "Stock_Profile" WHERE "Symbol" = 'MSFT'; '

错误：列 msft不存在
第1行：从 Stock_Profile中删除 WHERE Symbol = MSFT;

ERROR: column "msft" does not exist LINE 1: DELETE FROM "Stock_Profile" WHERE "Symbol" = MSFT;

如何显示psql MSFT是字符串？

How do I show psql that MSFT is a string?

它不喜欢'MSFT'，\'MSFT\'或'MSFT'

It does not like 'MSFT', \'MSFT\' or ''MSFT''

推荐答案

您遇到的问题是您已经用完了很多引号，无法嵌套；分开，我们有：

The problem you have is that you've run out of types of quote mark to nest; breaking apart, we have:

1. 您的shell需要将单个字符串传递给 psql 命令；这可以是单引号或双引号


2. 您的表名是大小写混合的，因此需要用双引号


3. 您的字符串需要用单引号引起来

1. your shell needs to pass a single string to the psql command; this can be either single quotes or double quotes
2. your table name is mixed case so needs to be double quoted
3. your string needs to be single quoted

在此示例中，您给出：

psql -E --host=xxx --port=yyy --username=chi --dbname=C_DB -c 'DELETE FROM "Stock_Profile" WHERE "Symbol" = 'MSFT'; '

shell看到两个单引号的字符串：

The shell sees two single-quoted strings:

• '从 Stock_Profile中删除符号 ='


• `'; ’

所以问题不在于psql，而在于shell本身。

So the problem is not in psql, but in the shell itself.

根据您使用的shell，单引号字符串可能不接受任何转义符（因此 \'没有帮助），但双引号字符串可能有用。因此，您可以尝试在外部查询上使用双引号，并在表名周围转义它们：

Depending on what shell you are using, single-quoted strings probably don't accept any escapes (so \' doesn't help) but double-quoted strings probably do. You could therefore try using double-quotes on the outer query, and escaping them around the table name:

psql -E --host=xxx --port=yyy --username=chi --dbname=C_DB -c "DELETE FROM \"Stock_Profile\" WHERE \"Symbol\" = 'MSFT'; "

现在 \ 不会结束字符串，因此shell会将其视为单个字符串：

Now the \" won't end the string, so the shell will see this as a single string:

"DELETE FROM \"Stock_Profile\" WHERE \"Symbol\" = 'MSFT'; "

并将其转义到带有处理的转义的psql中，从而产生所需的SQL：

and pass it into psql with the escapes processed, resulting in the desired SQL:

DELETE FROM "Stock_Profile" WHERE "Symbol" = 'MSFT'; 

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