## What about MONTH and YEAR functions?

 Author Message ruben ruvalcaba Valued Member Group: General Forum Members Points: 55 Visits: 104 Hi, First of all thank you, it's a good point to be considered. In fact, I use functions on the WHERE clause very often, specially when filtering dates ... how do you optimize a query like this: SELECT SUM(Amount) FROM myEntries WHERE YEAR(myEntries.myDate) = @Year AND MONTH(myEntries.myDate) <= @MonthAny clue? thank you regards Michael Valentine Jones SSC-Dedicated Group: General Forum Members Points: 35752 Visits: 11933 Do queries like this as a selection against a range in this form:where date >= @StartOfRange and date < @EndOf RangeIn the following code, it will be the same as this:where date >= '2008-01-01' and date < '2008-03-01'`declare @year intdeclare @month intselect @year = 2008, @month = 2select *from MyTablewhere -- Date on or after start of year MyTable.MyDate >= dateadd(month,(12*@Year)-22801+1,0) and -- Date before start of next month MyTable.MyDate < dateadd(month,(12*@Year)-22801+@Month+1,0)` Jack Corbett SSC Guru Group: General Forum Members Points: 103208 Visits: 15045 If this is how you will most often be querying your data you should have month and year columns in table with an index. Or, write your queries with explicit date ranges. If you want your users to be able to enter month and year paramters then convert them to dates after entry. So year=2008 and month=3 would become. Startdate=1/1/2008 & endate=3/31/2008. Jack Corbett Consultant Straight Path Solutions Dont let the good be the enemy of the best. -- Paul FlemingAt best you can say that one job may be more secure than another, but total job security is an illusion. -- Rod at workCheck out these links on how to get faster and more accurate answers: Forum Etiquette: How to post data/code on a forum to get the best helpNeed an Answer? Actually, No ... You Need a QuestionHow to Post Performance ProblemsCrosstabs and Pivots or How to turn rows into columns Part 1Crosstabs and Pivots or How to turn rows into columns Part 2 Lynn Pettis SSC Guru Group: General Forum Members Points: 223230 Visits: 40398 here is a slight variation to what Michael Valentine Jones provided:`declare @year smallint, @month tinyintset @year = 2007set @month = 2select sum(Amount)from dbo.myEntrieswhere myEntries.myDate >= dateadd(yy,(@year - 1900), 0) and myEntries.myDate < dateadd(mm, @month, dateadd(yy,(@year - 1900), 0))` Lynn PettisFor better assistance in answering your questions, click hereFor tips to get better help with Performance Problems, click hereFor Running Totals and its variations, click here or when working with partitioned tablesFor more about Tally Tables, click hereFor more about Cross Tabs and Pivots, click here and hereManaging Transaction LogsSQL Musings from the Desert Fountain Valley SQL (My Mirror Blog) Jack Corbett SSC Guru Group: General Forum Members Points: 103208 Visits: 15045 The thing about functions in where clauses is that, if on a column, you have to run every row through the function while using them on a parameter or constant the optimizer can run it once. This is why Michael's and Lynn's solutions are more effecient. Jack Corbett Consultant Straight Path Solutions Dont let the good be the enemy of the best. -- Paul FlemingAt best you can say that one job may be more secure than another, but total job security is an illusion. -- Rod at workCheck out these links on how to get faster and more accurate answers: Forum Etiquette: How to post data/code on a forum to get the best helpNeed an Answer? Actually, No ... You Need a QuestionHow to Post Performance ProblemsCrosstabs and Pivots or How to turn rows into columns Part 1Crosstabs and Pivots or How to turn rows into columns Part 2 Jeff Moden SSC Guru Group: General Forum Members Points: 505817 Visits: 44255 For too many reasons to list in this short amount of space, I strongly recommend that you never process dates by individual Year and/or Month components. Some of the others have already suggested how to handle things... always treat dates as a range... yep... even if the date is for one measely day. WHERE clauses should always follow the general format of...` WHERE somedatecol >= @StartDate AND somedatecol < @EndDate+1`That is assuming, of course, that you are working with whole dates that either have no literally expressed time component (defaults to midnight) or has a time component of precisely 00:00:00.000. Other considerations will need be made if @StartDate or @EndDate have a non-midnight time component. Doesn't matter if "somedatecol" does or not and that's the beauty of the method shown above. And, it'll allow for very high performance Index SEEKs if the correct indexes are available.You will also find those that suggest that you use one of the following...` WHERE somedatecol BETWEEN @StartDate AND DATEADD(ms,-3,@EndDate+1) WHERE somedatecol BETWEEN @StartDate AND @EndDate+'23:59:59.997`Treat them just like street drugs... just say "NO". Do they work? Yes, today they do... when 2008 comes out, it will "depend". --Jeff ModenRBAR is pronounced ree-bar and is a Modenism for Row-By-Agonizing-Row.First step towards the paradigm shift of writing Set Based code: Stop thinking about what you want to do to a row... think, instead, of what you want to do to a column.If you think its expensive to hire a professional to do the job, wait until you hire an amateur. -- Red Adair Helpful Links:How to post code problemsHow to post performance problemsForum FAQs