如何使用 LIKE 查询在 PostgreSQL 中找到文字百分号 (%)？
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How can you find a literal percent sign (%) in PostgreSQL using a LIKE query?
提问by magnus
I have character varyingentries in a table where some(not all) values contain percentages, e.g., '12%', '97%', etc. I want to find all the values that contain percentages. In other words, I want to find all values that end with a percent sign ('%').
我有character varying一个表项，其中一些（不是全部）值包含百分比，如'12%'，'97%'等我想找到所有包含百分比值。换句话说，我想找到所有以百分号 ( '%')结尾的值。
回答by Rahul Tripathi
You can try like this:
你可以这样试试：
SELECT * FROM my_table WHERE my_column LIKE '%\%%' ESCAPE '\';
Format
格式
<like predicate> ::=
<match value> [ NOT ] LIKE <pattern>
[ ESCAPE <escape character> ]
<match value> ::= <character value expression>
<pattern> ::= <character value expression>
<escape character> ::= <character value expression>
回答by Patrick
You have to escape the literal % sign. By default the escape character is the backslash:
您必须转义文字 % 符号。默认情况下，转义字符是反斜杠：
SELECT * FROM my_table WHERE my_column LIKE '%\%';
In this case the first %sign matches any starting sequence in my_column. The remaining \%are interpreted as a literal % character. The combination is therefore: match anything that ends in a % character.
在这种情况下，第一个%符号匹配 中的任何起始序列my_column。其余的\%被解释为文字 % 字符。因此，组合是：匹配以 % 字符结尾的任何内容。
回答by magnus
I ended up using regular expressions:
我最终使用了正则表达式：
select * from my_table where my_column ~ '%$';
However, I'd still like to know if it's possible using the LIKEoperator/comparison.
但是，我仍然想知道是否可以使用LIKE运算符/比较。
