Rounding a datetime value down to the nearest half hour

Question

I have a requirement to round a datetime2 value down to the nearest half hour. For example \'10/17/2013 12:10:00.123\' would round down to \'10/17/2013 12:00:00.0\' And \'10

Answer 1

@Twinkles's answer works well in SQL server to round to closest half an hour.

However, in development, strongly recommend use FLOOR to round to last half an hour.

SELECT CONVERT(datetime, FLOOR(CAST([columnname] AS float) * 48.0)/48.0) FROM [tableName]