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[英]How to post new records in sql in an existing table where my column has all NULL values?
[英]How to check if a column has all null values in a table? snowflake sql
我想看看在我的表中是否存在一个列,其所有行都是 null。
SELECT * FROM yourTableName
WHERE yourSpecificColumnName IS NULL
-> 这只会返回 null 的值,但我不知道 yourSpecificColumnName 是否在整个表格中完全是 null
将COUNT与HAVING
结合使用:
数数
返回指定列的非 NULL 记录数或记录总数。
SELECT 'Entire_column_is_empty'
FROM yourTable
HAVING COUNT(yourSpecificColumnName) = 0;
或QUALIFY
:
SELECT *
FROM yourTable
QUALIFY COUNT(yourSpecificColumnName) OVER() = 0;
替代方法:
SELECT 'Entire_column_is_empty'
FROM yourTable
HAVING MIN(yourSpecificColumnName) = MAX(yourSpecificColumnName);
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