max

问题 the table is: create table test ( id string, name string, age string, modified string) data like this: id name age modifed 1 a 10 2011-11-11 11:11:11 1 a 11 2012-11-11 12:00:00 2 b 20 2012-12-10 10:11:12 2 b 20 2012-12-10 10:11:12 2 b 20 2012-12-12 10:11:12 2 b 20 2012-12-15 10:11:12 I want to get the latest record(include every colums id,name,age,modifed) group by id,as the data above,the correct result is: 1 a 11 2012-11-11 12:00:00 2 b 20 2012-12-15 10:11:12 I do like this: insert

问题 Various online services have different values for maximum year of expiry, when it comes to Credit Cards. For instance: Basecamp: +15 years (2025) Amazon: +20 years (2030) Paypal: +19 years (2029) What is the reasonable maximum here? Are there any official guidelines? 回答1: There is no official guideline as the credit card issuers can choose each when the cards they issue will expire. In fact they have been issuing cards for longer and longer periods of time. If you're trying to determine how

问题 Suppose I have two tables A{int m} and B{int m} and I have to find maximum m among two tables using relational algebra but I cannot use max function.How can I do it?I think using join we can do it but i am not sure if my guess is correct or not. Note: this is an interview question. 回答1: Hmm, I'm puzzled why the question involves two tables. For the question as asked, I would just UNION the two (as StilesCrisis has done), then solve for a single table. So: how to find the maximum m in a table

问题 I have a query like below: select * from (select centre_name, sum(qty) as number1 from (select exchange_from_centre_id as cenid, count(exchange_from_centre_id) as qty from as2.exchange group by exchange_from_centre_id union all select exchange_to_centre_id as cenid, count(exchange_to_centre_id) as qty from as2.exchange group by exchange_to_centre_id), as2.centre c where c.centre_id = cenid group by centre_name); and this is the result: Name of the centre and the number of exchange Alice

问题 I am trying to use sapply to get the max date in a column but it is returning a number instead of a date. Any idea how to resolve this? I can't seem to figure out why this is occurring.. mtcars$datecolm = '2015-03-03' mtcars$datecolm[1] = '2015-09-09' mtcars$datecolm = as.Date(mtcars$datecolm) sapply(mtcars, max) # why is it returning a number instead of a date?? max(mtcars$datecolm) # works correctly Please use sapply given the way I have set this up... I know this works with apply(mtcars,2

问题 Set $i=0 and do ++$i while it increases. Which number we would reach? Note that it may be not the same as maximum integer in Perl (as asked in the title), because there may be gaps between adjacent integers which are greater than 1 . 回答1: "Integer" can refer to a family of data types ( int16_t , uint32_t , etc). There's no gap in the numbers these can represent. "Integer" can also refer to numbers without a fractional component, regardless of the type of the variable used to store it. ++ will

问题 The C++ standard library's max_element algorithm requires the iterators passed as inputs to model ForwardIterator . My understanding is that ForwardIterator refines InputIterator by specifying that you can use a ForwardIterator to iterate over the same range multiple times. Therefore, multi-pass algorithms require ForwardIterator s. However, max_element is not a multi-pass algorithm - it is sufficient to iterate over a range once to determine its maximum element. So why does max_element need

问题 The C++ standard library's max_element algorithm requires the iterators passed as inputs to model ForwardIterator . My understanding is that ForwardIterator refines InputIterator by specifying that you can use a ForwardIterator to iterate over the same range multiple times. Therefore, multi-pass algorithms require ForwardIterator s. However, max_element is not a multi-pass algorithm - it is sufficient to iterate over a range once to determine its maximum element. So why does max_element need

问题 I try to run this query on my custom contentprovider. cursor = activity.getContentResolver().query( GoalDescriptor.CONTENT_URI, "max(priority)", null, null, null); to obtain the max value of priority int column. i tried also : cursor = activity.getContentResolver().query( GoalDescriptor.CONTENT_URI, null, "max(priority)", null, null); whit no success. This code return this exception: java.lang.IllegalArgumentException: Invalid column MAX(priority) E/DatabaseUtils( 688): at android.database

问题 This question already has answers here : Index of max and min value in an array (3 answers) Closed 5 years ago . I'm trying to find the maximum value of a certain column in a matrix. I want to find both the maximum value and the index of the row in which it is. How can I do this? 回答1: max command can find both the maximal value and its index. Here's an example: >> A = randn(10,3) A = 0.8884 -0.10224 -0.86365 -1.1471 -0.24145 0.077359 -1.0689 0.31921 -1.2141 -0.8095 0.31286 -1.1135 -2.9443 -0