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How to round an average to 2 decimal places in PostgreSQL?
... round that takes a precision is only available for numeric.
regress=> SELECT round( float8 '3.1415927', 2 );
ERROR: function round(double precision, integer) does not exist
regress=> \df *round*
List of functions
Schema | Name | Result data type | Argument...
PostgreSQL - fetch the row which has the Max value for a column
...sted index lookup into lives - on my machine
-- the latter query plan was selected given my memory settings and
-- histogram
SELECT
l1.*
FROM
lives AS l1
INNER JOIN (
SELECT
usr_id,
MAX(time_stamp) AS time_stamp_max
FROM
lives
GROUP BY
usr_id
) AS l2
...
How to use GROUP_CONCAT in a CONCAT in MySQL
...
select id, group_concat(`Name` separator ',') as `ColumnName`
from
(
select
id,
concat(`Name`, ':', group_concat(`Value` separator ',')) as `Name`
from mytbl
group by
id,
`Name`
) tbl
group by id;
...
SQL RANK() versus ROW_NUMBER()
...he first 3 rows are tied when ordered by ID)
WITH T(StyleID, ID)
AS (SELECT 1,1 UNION ALL
SELECT 1,1 UNION ALL
SELECT 1,1 UNION ALL
SELECT 1,2)
SELECT *,
RANK() OVER(PARTITION BY StyleID ORDER BY ID) AS 'RANK',
ROW_NUMBER() OVER(PARTITION BY Style...
LINQ query to select top five
...
var list = (from t in ctn.Items
where t.DeliverySelection == true && t.Delivery.SentForDelivery == null
orderby t.Delivery.SubmissionDate
select t).Take(5);
share
...
Which selector do I need to select an option by its text?
I need to check if a <select> has an option whose text is equal to a specific value.
16 Answers
...
How to avoid the “divide by zero” error in SQL?
...rder to avoid a "Division by zero" error we have programmed it like this:
Select Case when divisor=0 then null
Else dividend / divisor
End ,,,
But here is a much nicer way of doing it:
Select dividend / NULLIF(divisor, 0) ...
Now the only problem is to remember the NullIf bit, if I use the "/"...
Populating a razor dropdownlist from a List in MVC
...leaner separation.
First create a viewmodel to store the Id the user will select along with a list of items that will appear in the DropDown.
ViewModel:
public class UserRoleViewModel
{
// Display Attribute will appear in the Html.LabelFor
[Display(Name = "User Role")]
public int Sele...
How do I map lists of nested objects with Dapper
... probably work:
Grab the courses:
var courses = cnn.Query<Course>("select * from Courses where Category = 1 Order by CreationDate");
Grab the relevant mapping:
var mappings = cnn.Query<CourseLocation>(
"select * from CourseLocations where CourseId in @Ids",
new {Ids = course...
Count table rows
...
SELECT COUNT(*) FROM fooTable;
will count the number of rows in the table.
See the reference manual.
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