SQL Last 6 Months

Try this one

where datediff(month, datetime_column, getdate()) <= 6

To exclude or filter out future dates

where datediff(month, datetime_column, getdate()) between 0 and 6

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This part datediff(month, datetime_column, getdate()) will get the month difference in number of current date and Datetime_Column and will return Rows like:

Result
1
2
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6
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10

This is Our final condition to get last 6 months data

where result <= 6

In SQL Server

where datetime_column > dateadd(m, -6, getdate() - datepart(d, getdate()) + 1)

SQLFiddle demo

In MySQL

where datetime_column > curdate() - interval (dayofmonth(curdate()) - 1) day - interval 6 month

SQLFiddle demo

.... where yourdate_column > DATE_SUB(now(), INTERVAL 6 MONTH)

For MS SQL Server, you can use:

where datetime_column >= Dateadd(Month, Datediff(Month, 0, DATEADD(m, -6,
current_timestamp)), 0)