blocks|key|2762975|text|标识符(包括列名)是的，而不是双引号的，在PostgreSQL中会折叠成小写。使用双引号创建并因此保留大写字母(和/或其他语法冲突)的列名在其余生中必须使用双引号：|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|2762976|"first_Name"|code-block|syntax|javascript|2762977|值(字符串文字/常量)用单引号括起来|2762978|'xyz'|2762979|因此，是的，PostgreSQL列名是区分大小写的(当使用双引号时)：|2762980|SELECT+*+FROM+persons+WHERE+"first_Name"+=+'xyz';|2762981|Read+the+manual+on+identifiers+here.|2762982|我的建议是只使用合法的小写名称，这样就不需要双引号了。|2762983|entityMap|0|LINK|mutability|MUTABLE|url|https://www.postgresql.org/docs/current/sql-syntax-lexical.html#SQL-SYNTAX-IDENTIFIERS^0|0|3|A|5|15|3|0|0|0|1|C|3|0|0|0|0|0|10|0|0|0^^$0|@$1|2|3|4|5|6|7|14|8|@$9|15|A|16|B|C]|$9|17|A|18|B|C]|$9|19|A|1A|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|1B|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|1C|8|@$9|1D|A|1E|B|C]|$9|1F|A|1G|B|C]]|D|@]|E|$]]|$1|M|3|N|5|H|7|1H|8|@]|D|@]|E|$I|J]]|$1|O|3|P|5|6|7|1I|8|@]|D|@]|E|$]]|$1|Q|3|R|5|H|7|1J|8|@]|D|@]|E|$I|J]]|$1|S|3|T|5|6|7|1K|8|@]|D|@$9|1L|A|1M|1|1N]]|E|$]]|$1|U|3|V|5|6|7|1O|8|@]|D|@]|E|$]]|$1|W|3|-4|5|6|7|1P|8|@]|D|@]|E|$]]]|X|$Y|$5|Z|10|11|E|$12|13]]]]

Identifiers (including column names) that are not double-quoted are folded to lowercase in PostgreSQL. Column names that were created with double-quotes and thereby retained uppercase letters (and/or other syntax violations) have to be double-quoted for the rest of their life:
<pre><code>&quot;first_Name&quot;
</code></pre>
Values (string literals / constants) are enclosed in single quotes:
<pre><code>'xyz'
</code></pre>
So, yes, PostgreSQL column names are case-sensitive (when double-quoted):
<pre><code>SELECT * FROM persons WHERE &quot;first_Name&quot; = 'xyz';
</code></pre>
<a href="https://www.postgresql.org/docs/current/sql-syntax-lexical.html#SQL-SYNTAX-IDENTIFIERS" rel="noreferrer">Read the manual on identifiers here.</a>
My standing advice is to use legal, lower-case names exclusively so double-quoting is not needed.

blocks|key|165783|text|引用documentation|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|165784|165785|关键字和未加引号的标识符不区分大小写。因此：|blockquote|165786|165787|更新MY_TABLE集合A=+5；|165788|可以等效地写成：|165789|uPDaTE+my_TabLE+SeT+a=+5；|165790|165791|您也可以使用带引号的标识符编写它|165792|UPDATE+"my_table"+SET+"a"+=+5;|code-block|syntax|javascript|165793|引用标识符使其区分大小写，而未加引号的名称始终折叠为小写(与SQL标准中未引用的名称折叠为大写不同)。例如，PostgreSQL认为标识符FOO、foo和"foo"是相同的，但是"Foo"和"FOO"是不同的。|style|CODE|165794|如果你想编写可移植的应用程序，建议你总是引用一个特定的名称，或者永远不要引用它。|165795|entityMap|0|LINK|mutability|MUTABLE|url|http://www.postgresql.org/docs/current/interactive/sql-syntax-lexical.html#SQL-SYNTAX-IDENTIFIERS^0|2|D|0|0|0|0|0|0|0|0|0|0|0|1X|3|21|3|25|5|2H|5|2N|5|0|0^^$0|@$1|2|3|4|5|6|7|1A|8|@]|9|@$A|1B|B|1C|1|1D]]|C|$]]|$1|D|3|-4|5|6|7|1E|8|@]|9|@]|C|$]]|$1|E|3|F|5|G|7|1F|8|@]|9|@]|C|$]]|$1|H|3|-4|5|6|7|1G|8|@]|9|@]|C|$]]|$1|I|3|J|5|6|7|1H|8|@]|9|@]|C|$]]|$1|K|3|L|5|6|7|1I|8|@]|9|@]|C|$]]|$1|M|3|N|5|6|7|1J|8|@]|9|@]|C|$]]|$1|O|3|-4|5|6|7|1K|8|@]|9|@]|C|$]]|$1|P|3|Q|5|6|7|1L|8|@]|9|@]|C|$]]|$1|R|3|S|5|T|7|1M|8|@]|9|@]|C|$U|V]]|$1|W|3|X|5|6|7|1N|8|@$A|1O|B|1P|Y|Z]|$A|1Q|B|1R|Y|Z]|$A|1S|B|1T|Y|Z]|$A|1U|B|1V|Y|Z]|$A|1W|B|1X|Y|Z]]|9|@]|C|$]]|$1|10|3|11|5|6|7|1Y|8|@]|9|@]|C|$]]|$1|12|3|-4|5|6|7|1Z|8|@]|9|@]|C|$]]]|13|$14|$5|15|16|17|C|$18|19]]]]

To quote the <a href="http://www.postgresql.org/docs/current/interactive/sql-syntax-lexical.html#SQL-SYNTAX-IDENTIFIERS" rel="noreferrer">documentation</a>:

<blockquote>
 Key words and unquoted identifiers are case insensitive. Therefore:

<pre><code>UPDATE MY_TABLE SET A = 5;
</code></pre>
 
 can equivalently be written as:

<pre><code>uPDaTE my_TabLE SeT a = 5;
</code></pre>
</blockquote>

You could also write it using quoted identifiers:

<pre><code>UPDATE "my_table" SET "a" = 5;
</code></pre>

Quoting an identifier makes it case-sensitive, whereas unquoted names are always folded to lower case (unlike the SQL standard where unquoted names are folded to upper case). For example, the identifiers <code>FOO</code>, <code>foo</code>, and <code>"foo"</code> are considered the same by PostgreSQL, but <code>"Foo"</code> and <code>"FOO"</code> are different from these three and each other.

If you want to write portable applications you are advised to always quote a particular name or never quote it.

blocks|key|166849|text|在PostgresQL中，大小写混合或大写的列名必须用双引号引起来。因此，最好的约定是在所有小写字母后面加上下划线。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|166850|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

The column names which are mixed case or uppercase have to be double quoted in PostgresQL. So best convention will be to follow all small case with underscore.

blocks|key|166852|text|如果使用JPA，我建议更改为小写模式、表和列名，您可以使用下面的说明来帮助您：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|166853|select
++++psat.schemaname,
++++psat.relname,
++++pa.attname,
++++psat.relid
from
++++pg_catalog.pg_stat_all_tables+psat,
++++pg_catalog.pg_attribute+pa
where
++++psat.relid+=+pa.attrelid|code-block|syntax|javascript|166854|更改架构名称：|166855|ALTER+SCHEMA+"XXXXX"+RENAME+TO+xxxxx;|166856|更改表名称：|166857|ALTER+TABLE+xxxxx."AAAAA"+RENAME+TO+aaaaa;|166858|更改列名：|166859|ALTER+TABLE+xxxxx.aaaaa+RENAME+COLUMN+"CCCCC"+TO+ccccc;|166860|entityMap^0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|W|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|Y|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|Z|8|@]|9|@]|A|$E|F]]|$1|O|3|P|5|6|7|10|8|@]|9|@]|A|$]]|$1|Q|3|R|5|D|7|11|8|@]|9|@]|A|$E|F]]|$1|S|3|-4|5|6|7|12|8|@]|9|@]|A|$]]]|T|$]]

if use JPA I recommend change to lowercase schema, table and column names, you can use next intructions for help you:
<pre><code>select
 psat.schemaname,
 psat.relname,
 pa.attname,
 psat.relid
from
 pg_catalog.pg_stat_all_tables psat,
 pg_catalog.pg_attribute pa
where
 psat.relid = pa.attrelid
</code></pre>
change schema name:
<pre><code>ALTER SCHEMA &quot;XXXXX&quot; RENAME TO xxxxx;
</code></pre>
change table names:
<pre><code>ALTER TABLE xxxxx.&quot;AAAAA&quot; RENAME TO aaaaa;
</code></pre>
change column names:
<pre><code>ALTER TABLE xxxxx.aaaaa RENAME COLUMN &quot;CCCCC&quot; TO ccccc;
</code></pre>

blocks|key|2763183|text|您可以尝试使用此示例以大写字母命名表和列。(postgresql)|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2763184|//Sql;
++++++create+table+"Test"
++++++++(
++++++++"ID"+integer,
++++++++"NAME"+varchar(255)
++++++++)



//C#
++string+sqlCommand+=+$@"create+table+""TestTable""+(
++++++++++++++++++++++++++++++++""ID""+integer+GENERATED+BY+DEFAULT+AS+IDENTITY+primary+key,+
++++++++++++++++++++++++++++++++""ExampleProperty""+boolean,
++++++++++++++++++++++++++++++++""ColumnName""+varchar(255))";|code-block|syntax|javascript|2763185|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

You can try this example for table and column naming in capital letters. (postgresql)
<pre><code>//Sql;
 create table &quot;Test&quot;
 (
 &quot;ID&quot; integer,
 &quot;NAME&quot; varchar(255)
 )



//C#
 string sqlCommand = $@&quot;create table &quot;&quot;TestTable&quot;&quot; (
 &quot;&quot;ID&quot;&quot; integer GENERATED BY DEFAULT AS IDENTITY primary key, 
 &quot;&quot;ExampleProperty&quot;&quot; boolean,
 &quot;&quot;ColumnName&quot;&quot; varchar(255))&quot;;
</code></pre>

I have a db table say, <code>persons</code> in Postgres handed down by another team that has a column name say, <code>"first_Name"</code>. Now am trying to use PG commander to query this table on this column-name.

<pre><code>select * from persons where first_Name="xyz";
</code></pre>

And it just returns

<blockquote>
 ERROR: column "first_Name" does not exist
</blockquote>

Not sure if I am doing something silly or is there a workaround to this problem that I am missing?

Are PostgreSQL column names case-sensitive?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我有一个数据库表，在Postgres中是由另一个团队传递的，它的列名是"first_Name"。现在，我尝试使用PG commander在这个列名上查询这个表。select * from persons where first_Name="xyz";然后它就会返回错误:列"first_Name“不存在不确定我是否在做一些愚蠢的事情，或者是否有解决这个问题的方法我错过了？

问PostgreSQL列名是否区分大小写？
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问PostgreSQL列名是否区分大小写？
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