sql - 使用 "select trim"时如何避免postgresql更改列名

Question

我在我的 PostgreSql 版本 9.3 中运行以下查询(我正在使用 PgAdmin III):

Select trim(both ' ' from column1) from myTable

它返回我想要的数据，但它还将列名称从 'column1' 重命名为 'btrim'。我需要原始列名称，因为我正在使用来自 Java 应用程序的查询。这种重命名发生在我使用 Trim 函数的所有列上，无论我是直接在 pgAdmin 中运行查询还是通过我的 postgres jdbc driver 运行查询。 (这就是为什么我认为问题出在 postgres 本身)。

如何在使用 Trim 函数时获取正确名称的数据和列？

Answer 1

使用列别名:

Select trim(both ' ' from column1) AS column1 
from myTable

SqlFiddleDemo

如果您需要区分大小写的别名，您需要用 " 将它们引起来。

Idenfifiers:

Quoting an identifier also makes it case-sensitive, whereas unquotednames are always folded to lower case. For example, the identifiersFOO, foo, and "foo" are considered the same by PostgreSQL, but "Foo"and "FOO" are different from these three and each other. (The foldingof unquoted names to lower case in PostgreSQL is incompatible with theSQL standard, which says that unquoted names should be folded to uppercase. Thus, foo should be equivalent to "FOO" not "foo" according tothe standard. If you want to write portable applications you areadvised to always quote a particular name or never quote it.)