在 Teradata 中查找具有 NULL 值的列 [英] Find columns with NULL values in Teradata

问题描述

我想在表中查找包含空值的列.是否有包含该信息的系统表?

I would like to find the columns in a table that has a null value in it. Is there a system table that have that information?

推荐答案

要查找允许空"值的列，请尝试...

To find columns where "null" values are allowed try...

select *
from dbc.columns 
where databasename = 'your_db_name'
and tablename = 'your_table_name'
and Nullable = 'Y'

然后要识别具有空值的特定行，从之前的结果集中获取ColumnName"并运行查询以识别结果......如果您想对它们采取进一步的行动，也许将它们扔到一个易失性表中(更新、删除).

then to identify the specific rows w/ null values, take the "ColumnName" from the previous result set and run queries to identify results... perhaps throw them in a volatile table if you want to take further action on them (update,delete).

-- for example you found out that column "foo" is nullable... 
create volatile table isnull_foo_col
as
(
  sel * 
  from your_table_name 
  where foo is null
) with data 
on commit preserve rows;

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