SQLite 喜欢 % 和 _ [英] SQLite Like % and _

问题描述

我无法弄清楚 SQLite like 语句中下划线字符的作用.通配符 % 可能与大多数其他 SQL 数据库中的相同.

I can't figure out what the underscore character does in an SQLite like statement. The wildcard character, %, is probably the same as in most other SQL databases.

那么，_ 字符有什么作用?

So, what does the _ character do?

推荐答案

下划线也与大多数其他 SQL 数据库中的相同，匹配任何单个字符(即与 . 中的相同)正则表达式).来自精美手册:

The underscore is also the same as in most other SQL databases and matches any single character (i.e. it is the same as . in a regular expression). From the fine manual:

LIKE 模式中的下划线(_")匹配字符串中的任何单个字符.

An underscore ("_") in the LIKE pattern matches any single character in the string.

例如:

-- The '_' matches the single 'c'
sqlite> select 'pancakes' like 'pan_akes';
1
-- This would need '__' to match the 'ca', only one '_' fails.
sqlite> select 'pancakes' like 'pan_kes';
0
-- '___' also fails, one too many '_'.
sqlite> select 'pancakes' like 'pan___kes';
0

为了确保结果有意义:SQLite 使用0 和 1 表示布尔值.

And just to make sure the results make sense: SQLite uses zero and one for booleans.

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