SQLite 中字符串字面量和标识符的区别 [英] Difference between String Literal and Identifier in SQLite

问题描述

字符串文字和标识符有什么区别?我试着用谷歌搜索这个，结果更困惑

What's the difference between a string literal and an identifier? I tried googling this and ended up being more confused

对 Python 的差异和 SQLite 的差异特别感兴趣

Specifically interested with the difference in Python, and difference in SQLite

来自 SQLite 文档

From SQLite Documentation

'keyword'       A keyword in single quotes is a string literal.
"keyword"       A keyword in double-quotes is an identifier.

参考文档https://docs.python.org/3/reference/lexical_analysis.html#identifiershttps://www.sqlite.org/lang_keywords.html

推荐答案

标识符是一个变量名.在以下 python 行中

An identifier is a variable name. In the following python line

foo = "bar"

foo 是一个标识符，bar"是一个标识符.是字符串文字.在 Python 中，字符串文字可以用简单的 ('') 或双引号 (") 括起来.

foo is an identifier and "bar" is a string literal. In Python, string literal can be enclosed in simple ('') or double (") quotes.

在 SQLite 中(更普遍的是在 SQL 中)，字符串文字用单引号括起来.双引号用于强制将包含特殊字符的字符串解释为标识符.

In SQLite (and more generally in SQL), string literals are enclosed in single quotes. Double quotes are use to force a string containing otherwise special characters to be interpreted as identifiers.

假设表 foo 与列 bar 的示例:

Example assuming a table foo with column bar :

SELECT bar as "Bar", 'zz' as OTHER from foo;

在此选择中，第一列的名称为 Bar.如果没有 "，名称将是 bar，因为 SQL 通常不区分大小写.第二列是常量 zz，列名是 other.

In this select, the first column will have name Bar. Without the ", the name would have been bar since SQL does not normally distinguishes case. The second column will the the constant zz and the column name will be other.

对于非英语语言，" 也可用于具有重音字符，例如 éè.

The " are also useful to have accented chars like éè for non english languages.

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