I've two string fields which contains dates in string like field_1 = "2003.11.14" and I use them in ORM and they are working just fine. Now I want to compare 1 field value with another field's - 18.months. Here is a example
User.where("users.field_1 > '#{Date.today - 18.months}' AND users.field_2 > (users.fields_1 - 18.months)")
something like. Can anyone help me?
Thanks in advance
Most databases support data calculations in SQL. Something like this should work.
query = User.where("users.field_1 > ?", 18.months.ago)
query.where("users.field_2 > users.field_1 - :time", time: 18.months.ago)
edit: Just saw that the values are stored as strings, then you can not use SQL.
can not do that because the table has millions of records
I don't really understand why the size of the table limits to use the correct data type?
Related
I have several records in my database, the table has a column named "weekday" where I store a weekday like "mon" or "fri". Now from the frontend when a user does search the parameters posted to the server are startday and endDay.
Now I would like to retrieve all records between startDay and endDay. We can assume startDay is "mon" and endDay is "sun". I do not currently know how to do this.
Create another table with the names of the days and their corresponding number. Then you'd just need to join up your current table with the days table by name, and then use the numbers in that table to do your queries.
Not exactly practical, but it is possible to convert sun,mon,tue to numbers using MySQL.
Setup a static year and week number like 201610 for the 10th week of this year, then use a combination of DATE_FORMAT with STR_TO_DATE:
DATE_FORMAT(STR_TO_DATE('201610 mon', '%X%V %a'), '%w')
DATE_FORMAT(STR_TO_DATE('201610 sun', '%X%V %a'), '%w')
DATE_FORMAT(STR_TO_DATE('201610 tue', '%X%V %a'), '%w')
These 3 statements will evaluate to 0,1,2 respectively.
The main thing this is doing is converting the %a format (Sun-Sat) to the %w format (0-6)
well i don't know the architecture of your application as i think storing and querying a week day string is not appropriate, but i can tell you a work around this.
make a helper function which return you an array of weekdays in the range i-e
function getWeekDaysArray($startWeekDay, $endWeekDay) {
returns $daysArray['mon','tue','wed'];
}
$daysRangeArray = getWeekDaysArray('mon', 'wed');
now with this array you can query in table
DB::table('TableName')->whereIn('week_day', $daysRangeArray)->get();
Hope this help
This is too tough for me guys. It's for Jeremy!
I have two tables (although I can also envision needing to join a third table) and I want to sum one field and count rows, in the same, table while joining with another table and return the result in json format.
First of all, the data type field that needs to be summed, is numeric(10,2) and the data is inserted as params['amount'].to_f.
The tables are expense_projects which has the name of the project and the company id and expense_items which has the company_id, item and amount (to mention just the critical columns) - the "company_id" columns are disambiguated.
So, the following code:
expense_items = DB[:expense_projects].left_join(:expense_items, :expense_project_id => :project_id).where(:project_company_id => company_id).to_a.to_json
works fine but when I add
expense_total = expense_items.sum(:amount).to_f.to_json
I get an error message which says
TypeError - no implicit conversion of Symbol into Integer:
so, the first question is why and how can this be fixed?
Then I want to join the two tables and get all the project names form the left (first table) and sum amount and count items in the second table. I have tried
DB[:expense_projects].left_join(:expense_items, :expense_items_company_id => expense_projects_company_id).count(:item).sum(:amount).to_json
and variations of this, all of which fails.
I would like a result which gets all the project names (even if there are no expense entries and returns something like:
project item_count item_amount
pr 1 7 34.87
pr 2 0 0
and so on. How can this be achieved with one query returning the result in json format?
Many thanks, guys.
Figured it out, I hope this helps somebody else:
DB[:expense_projects___p].where(:project_company_id=>user_company_id).
left_join(:expense_items___i, :expense_project_id=>:project_id).
select_group(:p__project_name).
select_more{count(:i__item_id)}.
select_more{sum(:i__amount)}.to_a.to_json
I would be happy to get a good way to get the "table" structure from a plain SQL table.
In my specific case, I need to render JSON structure used by Google Visualization API "datatable" object:
http://code.google.com/apis/chart/interactive/docs/reference.html#DataTable
However, having an example in HTML would help either.
My "source" is a plain SQL table of "DailySales": its columns are "Day" (date), "Product" and "DailySaleTotal" (daily sale for that product). Please recall that my "model" reflects the 3-column table above.
The table columns should be "products" (suppose we have very small number of such). Each row should represent a specific date, and the row data are the actual sales for that day.
Date Product1 Product2 Product3
01/01/2012 30 50 60
01/02/2012 35 3 15
I was trying to use nested #{list} tags in a template, but unfortunately I failed to find a natural way to provide a template with a "list" to represent the "row data".
Of course, I can build a "helper object" in Java that will build a list of the "sales data" items per date - but this looks very weird to me.
I would be thankful to anyone who can provide an elegant solution.
Max
When you load your model order it by date and product name. Then in your controller build a map with date as index and list of model objects that have the same date as value of the map
Then in your template you have a first list iteration on map keys for the rows and a second list iteration on the list value for the columns.
Something like
[
#{list modelMap.keys, as: 'date'}
[${date},#{list modelMap.get(date), as: 'product'}${product.dailySaleTotal}#{ifnot product_isLast},#{/ifnot}#{/list}]#{ifnot date_isLast},#{/ifnot}
#{/list}
]
you can then adapt your json rendering to the exact structure you want to have. Here it is an array of arrays.
Instead of generating the JSON yourself, like Seb suggested, you can generate it:
private static Result queryToJsonResult(String sql) {
SqlQuery sqlQuery = Ebean.createSqlQuery(sql);
return ok(Json.toJson(sqlQuery.findList()));
}
I have a table in Mongo. One of the fields is a DateTime. I would like to be able to get all of the records that are only for a single day (i.e. 9/3/2011).
If I do something like this:
var list = (from c in col
where c.PublishDate == DateTime.Now
select c).ToList();
Then it doesn't work because it is using the time in the comparison. Normally I would just compare the ToShortDateString() but NoRM does not allow me to use this.
Thoughts?
David
The best way to handle this is normally to calculate the start datetime and end datetime for the date in question and then query for values in that range.
var start = DateTime.Now.Date;
var end = start.AddDays(1);
...
But you'd also be well advised to switch to the official C# driver now. You should also use UTC datetimes in your database (but that gets more complicated).
I am ran into the following issue.
Take a look at the following where clause.
Where(x => x.CreateTS <= dateParameters.CreationDate.ToDateValue &&
x.CreateTS >= dateParameters.CreationDate.FromDateValue)
CreateTS is a Timestamp column in the table. so when my dateparameters are todate = 01/28/2010 12:00A.M" fromdate= "01/26/2010 12.00A.M" (c# DateTime types) my query doesnot retrivies the table records whose CreateTS look like 01/28/2010 1:45A.M and above just differeing in the timestamps.
I just wanted to do comparison and dont want to compare the timestamps. any help would be appreciated.
Just look at the .Date portion of the DateTime:
Where(x => x.CreateTS.Date <= dateParameters.CreationDate.ToDateValue && x.CreateTS.Date >= dateParameters.CreationDate.FromDateValue)
As a side note:
Personally, I would put from first, since it's a bit easier to follow from a readability standpoint:
Where(x => x.CreateTS.Date >= dateParameters.CreationDate.FromDateValue && x.CreateTS.Date <= dateParameters.CreationDate.ToDateValue)
(I find it easier to think of being between two values as being >low and
Edit: You didn't specify that you were using the EF LINQ providers, which do not allow you to do Date. You can, I believe, handle this by looking forward one day, and using < instead of <= for your "to" comparison:
Where(x => x.CreateTS >= dateParameters.CreationDate.FromDateValue && x.CreateTS.Date < dateParameters.CreationDate.AddDays(1).ToDateValue)
#SARAVAN, AFAIK timestamp columns cannot be used in comparisons like that. A timestamp columns are mapped as byte[] (byte array) in EF. If comparisons like that are needed, I suggest to change the timestamp column in database to a datetime one.
only to quote from MSDN:
The SQL Server timestamp data type has nothing to do with times or dates. SQL Server timestamps are binary numbers that indicate the relative sequence in which data modifications took place in a database.
Interesting moment here is that
01/28/2010 12:00A.M actually in 24 hour format is 00:00 while 01/28/2010 1:45A.M is 01:45 and that seems to be the reason why those records are not returned. The midday will be 01/28/2010 12:00P.M