sql-order-by

问题 I had a question in MySQL, did it correctly. But the book code differs a little. Book: use tennis; select playerno, datediff(coalesce(end_date, current_date), begin_date) as Difference, position from committee_members where datediff(coalesce(end_date, current_date), begin_date) > 500 order by 1; What is this order by 1 ? My code also works and is almost the same except: select playerno, datediff(coalesce(end_date, current_date) AS Data, order by Data; 回答1: order by 1 means "order by the first

问题 I am using ormlite in my recent android project. I want to order by on a query on multiple columns in a table (say two columns). How can I achieve that?? Here is the code for a single order by... QueryBuilder<Visit, Integer> qb = getHelper().getVisitDao().queryBuilder(); qb.where().eq("FOREIGN_ID", id); qb.orderBy("VISIT_DATE", false); 回答1: I want to order by on a query on multiple columns in a table(say two columns). How can i achieve that?? All you need to do is to call orderBy(...)

问题 I've the below result VendorName | IncidentID | IncidentStatus | IncidentDate ------------------------------------------------------- XYZ | 100 | Open | 02-JUN-2011 XYZ | 101 | Open | 03-JUN-2011 ABC | 102 | Open | 01-JUN-2011 XYZ | 103 | Open | 01-APR-2011 ABC | 105 | Open | 05-JUN-2011 I want to order VendorName which has latest incident. Vendor ABC has the latest incident hence it should come first with all other incident for same vendor and then next Vendor with all respective incident in

问题 I have the following models: Product: name, shop_id (foreign key), brand_id (foreign key), price Shop: name Brand: name The associations are: Product: belongs_to :shop belongs_to :brand Shop: has_many :products has_many :brands, :through => :products Brand: has_many :products has_many :shops, :through => :products In ProductsController#list I would like to get a list of all products sorted by shop name and then by brand name. I tried to do: @products = Product.order("products.shop.name ASC,

问题 I'm using Laravel and MySQL, and I have a table post that represents post where users can comment on it, now I wanna order posts by the number of comments of each post in ascending/descending order, how do I do this in Laravel? I don't want to add a field in post table to keep track of the number of comments of each post, because updating that field manually each time a comment or a comment's comment is added/deleted drives me crazy... This is how I create my posts table and comments table:

问题 I have a mapping like this: @ManyToMany(cascade = CascadeType.PERSIST) @JoinTable( name="product_product_catalog", joinColumns={@JoinColumn(name="product_catalog", referencedColumnName="product_catalog")}, inverseJoinColumns={@JoinColumn(name="product", referencedColumnName="product")}) public List<Product> products = new ArrayList<Product>(); I can fetch the products for the catalog nicely, but I can't (dynamically) order the products. How could I order them? I probably have to write a many

问题 What is a good way to get the top 10 records from a very large collection and use a custom OrderBy? If I use the LINQ to Objects OrderBy method it is slow and takes a lot of memory because it creates an entire new collection with the new order. I would like a new method with the signature below that does not re-order the entire collection and is very fast: public static IEnumerable<TSource> OrderByTop<TSource, TKey>( IEnumerable<TSource> source, Func<TSource, TKey> keySelector, IComparer<TKey

问题 HI, I 'm trying to sort the rows in my datatable using select method. I know that i can say datatable.select("col1='test'") which in effect is a where clause and will return n rows that satisfy the condition. I was wondering can i do the following datatable.select("ORDER BY col1") ---col1 is the name of hte column I tried datatable.defaultview.sort() but didnt work Any ideas on how to get around this issue. thanks 回答1: Have you tried using the DataTable.Select(filterExpression, sortExpression

问题 I am in the process of switching my development environment from sqlite3 to postgresql 8.4 and have one last hurdle. In my original I had the following line in a helper method; result = Users.find(:all, :order => "name collate NOCASE") which provided a very nice case-insensitive search. I can't replicate this for postgresql. Should be easy - any ideas? Thanks. 回答1: result = Users.find(:all, :order => "LOWER(name)") To take a little bit from both Brad and Frank. 回答2: LanecH's answer adapted

问题 Which one comes first when MySQL processes the query? An example: SELECT pageRegions FROM pageRegions WHERE(pageID=?) AND(published=true) AND (publishedOn<=?) ORDER BY publishedON DESC LIMIT 1'; Will that return the last published pageRegion even if the record does not match the revision datetime IF LIMIT is applied after ORDER BY? 回答1: Yes, it's after the ORDER BY. For your query, you'd get the record with the highest publishedOn, since you're ordering DESC , making the largest value first