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如何計算sql server中非空列的百分比?如何計算sql server中非空列的百分比?
如何計算sql server中非空列的百分比?如何計算sql server中非空列的百分比?
如果你的意思是「我的表中有多少非空值有在某一列」:
SELECT
percentage=CASE WHEN (SELECT COUNT(*) FROM your_table)=0
THEN
NULL
ELSE
CAST((SELECT COUNT(*) FROM your_table WHERE your_column IS NOT NULL) AS FLOAT)/
(SELECT COUNT(*) FROM your_table)
END
如果全球的意思有多少非空列有在您的SQL Server中的所有表例如:
SELECT
percentage=
CAST((
SELECT
COUNT(*)
FROM
INFORMATION_SCHEMA.COLUMNS
WHERE
IS_NULLABLE='NO'
) AS FLOAT)/
(
SELECT
COUNT(*)
FROM
INFORMATION_SCHEMA.COLUMNS
)
歡迎來到SO,@Shilan。請閱讀,這將有助於您的下一個問題 - > http://codeblog.jonskeet.uk/2010/08/29/writing-the-perfect-question/ –