SQL：如何从日期时间字段中提取月份
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SQL: how to extract the month from a date time field
提问by mechalaris
I need to to extract the month from date time fieldA then put the result into fieldB as an integer in the same table IF fieldB is empty.
我需要从日期时间字段A中提取月份，然后将结果作为同一个表中的整数放入字段B，如果字段B为空。
eg) 1988-02-03 00:00:00.000I need to extract 02 and put the result into another field only if that field is empty.
例如）1988-02-03 00:00:00.000只有当该字段为空时，我才需要提取 02 并将结果放入另一个字段。
I guess this will end up as a stored procedure.
我想这最终会成为一个存储过程。
回答by juergen d
回答by Infinite Possibilities
MONTH(fieldA)or DATEPART(M, fieldA)
MONTH(fieldA)或者 DATEPART(M, fieldA)
回答by Matt Busche
SQL Server has a built-in function called month()that will return the month for date and timestamp data types
SQL Server 有一个内置函数month()，该函数将返回日期和时间戳数据类型的月份
UPDATE yourtable
SET newcolumn = month(columnname)
WHERE newcolumn IS NULL
