<t>Strictly, method a is the least resource intensive:<br/>
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a) select DATEADD(dd, DATEDIFF(dd, 0, getdate()), 0)<br/>
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```<br/>
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Proven less CPU intensive for the same total duration a million rows by someone with way too much time on their hands: [Most efficient way in SQL Server to get a date from date+time?](https://stackoverflow.com/questions/133081/most-efficient-way-in-sql-server-to-get-date-from-datetime)<br/>
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I saw a similar test elsewhere with similar results too.<br/>
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I prefer the DATEADD/DATEDIFF because:<br/>
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- varchar is subject to language/dateformat issues<br/>
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Example: [Why is my CASE expression non-deterministic?](https://stackoverflow.com/q/3596663/27535)<br/>
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- float relies on internal storage<br/>
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- it extends to work out first day of month, tomorrow, etc by changing "0" base<br/>
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**Edit, Oct 2011**<br/>
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For SQL Server 2008+, you can CAST to `date` i.e. `CAST(getdate() AS date)`. Or just use `date` datatype so no `time` to remove.<br/>
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**Edit, Jan 2012**<br/>
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A worked example of how flexible this is: [Need to calculate by rounded time or date figure in sql server](https://stackoverflow.com/questions/8722022/need-to-calculate-by-rounded-time-or-date-figure-in-sql-server/8723311#8723311)<br/>
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**Edit, May 2012**<br/>
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Do not use this in WHERE clauses and the like without thinking: adding a function or CAST to a column invalidates index usage. See number 2 here [Common SQL Programming Mistakes](http://www.simple-talk.com/sql/t-sql-programming/ten-common-sql-programming-mistakes/)<br/>
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Now, this does have an example of later SQL Server optimiser versions managing CAST to date correctly, but *generally* it will be a bad idea ...<br/>
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**Edit, Sep 2018, for datetime2**<br/>
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```<br/>
DECLARE @datetime2value datetime2 = '02180912 11:45' --this is deliberately within datetime2, year 0218<br/>
DECLARE @datetime2epoch datetime2 = '19000101'<br/>
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select DATEADD(dd, DATEDIFF(dd, @datetime2epoch, @datetime2value), @datetime2epoch)<br/>
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```</t>
