SQL 只需从 hive 表中获取列名
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Just get column names from hive table
提问by cantdutchthis
I know that you can get column names from a table via the following trick in hive:
我知道您可以通过 hive 中的以下技巧从表中获取列名：
hive> set hive.cli.print.header=true;
hive> select * from tablename;
Is it also possible to justget the column names from the table?
是否也可以只从表中获取列名？
I dislike having to change a setting for something I only need once.
我不喜欢为我只需要一次的东西更改设置。
My current solution is the following:
我目前的解决方案如下：
hive> set hive.cli.print.header=true;
hive> select * from tablename;
hive> set hive.cli.print.header=false;
This seems too verbose and against the DRY-principle.
这似乎过于冗长并且违反了 DRY 原则。
回答by JJFord3
If you simply want to see the column names this one line should provide it without changing any settings:
如果您只是想查看列名，这一行应该提供它而无需更改任何设置：
describe database.tablename;
However, if that doesn't work for your version of hive this code will provide it, but your default database will now be the database you are using:
但是，如果这不适用于您的 hive 版本，此代码将提供它，但您的默认数据库现在将是您正在使用的数据库：
use database;
describe tablename;
回答by Angelo Di Donato
you could also do show columns in $tableor see Hive, how do I retrieve all the database's tables columnsfor access to hive metadata
您还可以执行show columns in $table或查看Hive，如何检索所有数据库的表列以访问Hive元数据
回答by Alex Raj Kaliamoorthy
use desc tablenamefrom Hive CLI or beeline to get all the column names. If you want the column names in a file then run the below command from the shell.
使用desc tablenameHive CLI 或 beeline 获取所有列名称。如果您想要文件中的列名，请从 shell 运行以下命令。
$ hive -e 'desc dbname.tablename;' > ~/columnnames.txt
where dbnameis the name of the Hive database where your table is residing
You can find the file columnnames.txt in your root directory.
这里dbname是你的表是居住，您可以找到您的根目录下的文件columnnames.txt蜂房数据库的名称。
$cd ~
$ls
