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How to force LINQ Sum() to return 0 while source collection is empty
...word
&& l.Property.PropertyId == PropertyId)
.Select(l => l.Amount)
.DefaultIfEmpty(0)
.Sum();
This way, your query will only select the Amount field. If the collection is empty, it will return one element with the value of 0 and then the sum will ...
How do I check if an index exists on a table field in MySQL?
...
Try:
SELECT * FROM information_schema.statistics
WHERE table_schema = [DATABASE NAME]
AND table_name = [TABLE NAME] AND column_name = [COLUMN NAME]
It will tell you if there is an index of any kind on a certain column wi...
Hidden Features of Xcode
...m working with a large or unfamiliar project.
To show the Favorites Bar, select the following menu option:
View > Layout > Show Favorites Bar
share
edited Apr 4 '11...
Difference between a theta join, equijoin and natural join
...ed SQL query would be like this (you can play with all the examples here)
SELECT *
FROM Product
JOIN Component
ON Product.Pname = Component.Pname
and the result:
| PNAME | PRICE | CNAME | COST |
----------------------------------
| Laptop | 1500 | CPU | 500 |
| Laptop | 1500 | hdd ...
jQuery: Select data attributes that aren't empty?
I'm trying to select all elements that have a data-go-to attribute that is not empty.
11 Answers
...
how to schedule a job for sql query to run daily?
...QL Server Agent node and right click the Jobs node in SQL Server Agent and select 'New Job'
In the 'New Job' window enter the name of the job and a description on the 'General' tab.
Select 'Steps' on the left hand side of the window and click 'New' at the bottom.
In the 'Steps' window enter a step n...
How to get last N records with activerecord?
...e-wise - at least not up to Rails 3.1. SomeModel.last(5) will execute the select statement without a limit, returning all records of SomeModel to Ruby as an array, after which Ruby will pick out the last (5) elements. Efficiency-wise, currently, you want to use limit - particularly if you have pote...
Generating a UUID in Postgres for Insert statement?
...d to run psql -d dbname -f SHAREDIR/contrib/module.sql and now it works!!! select uuid_generate_v1(); returns 1 now now. Thanks so much!
– anon58192932
Sep 29 '12 at 22:13
5
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Escape Character in SQL Server
...s the second answer shows it's possible to escape single quote like this:
select 'it''s escaped'
result will be
it's escaped
If you're concatenating SQL into a VARCHAR to execute (i.e. dynamic SQL), then I'd recommend parameterising the SQL. This has the benefit of helping guard against SQL in...
Getting all selected checkboxes in an array
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function get_selected_checkboxes_array(){ var ch_list=Array(); $("input:checkbox[type=checkbox]:checked").each(function(){ch_list.push($(this).val());}); ...