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SQL - Calculate time difference in Minutes, Hours, Days, Weeks, Months, Years for Posts / Notification

In this post I will show you how you can easily calculate time difference between two dates in seconds, minutes, hours, days, and even weeks, months and years in SQL.

This functionality can be used in notifications, emails, blog post etc

The key of this calculation is in Modulo operator, %. It returns the remainder (NOT the result!) of one number divided by another!


CREATE FUNCTION [dbo].[FN_GetTimeDifference] (@FromDate DATETIME, @ToDate DATETIME) RETURNS NVARCHAR(50) AS BEGIN DECLARE @Result NVARCHAR(50) SELECT @Result = CASE WHEN DATEDIFF(second, @FromDate, @ToDate) / 60 / 60 / 24 / 7 > 0 THEN CAST(DATEDIFF(second, @FromDate, @ToDate) / 60 / 60 / 24 / 7 AS NVARCHAR(50)) + ' weeks ago' WHEN DATEDIFF(second, @FromDate, @ToDate) / 60 / 60 / 24 % 7 > 0 THEN CAST(DATEDIFF(second, @FromDate, @ToDate) / 60 / 60 / 24 % 7 AS NVARCHAR(50)) + ' days ago' WHEN DATEDIFF(second, @FromDate, @ToDate) / 60 / 60 % 24 > 0 THEN CAST(DATE…
Recent posts

Pass multiple complex objects to Web API action

Working with ASP.NET Web API, the most unexpected thing is the limited support of POST data values to simple ApiController methods.

When a parameter has [FromBody], Web API uses the Content-Type header to select a formatter. At most one parameter is allowed to read from the message body. The reason for this rule is that the request body might be stored in a non-buffered stream that can only be read once.

A simple principle, you can send any content in HTTP request, it only need to be serializable into a string. So, it could be multiple JSON object. In this example, the content type is "application/json" and the request body is a raw JSON string (not a JSON object).

Here I found a workaround to pass multiple complex objects (using the above principle) from jquery to a WEB API using JObject, and then cast back to your required specific object type in api controller. This objects provides a concrete type specifically designed for working with JSON.

var customer = { "Name&q…

Call User-defined Function on Linked Server :SQL Server

If you try to invoke a user-defined function (UDF) through a linked server in SQL Server by using a "four-part naming" convention (server.database.dbo.Function), you may receive error message. 
The reason is User-defined function calls inside a four-part linked server query are not supported in SQL Server. Thats why error message indicates that the syntax of a Transact-SQL statement is incorrect. 
To work around this problem, use the Openquery function instead of the four-part naming convention. For example, instead of the following query
Select * from Linked_Server.database.dbo.Function(10)
run a query with the Openquery function:
Select * from Openquery(Linked_Server,'select database.dbo.Function(10)') If the user-defined function takes variable or scalar parameters, you can use the sp_executesql stored procedure to avoid this behavior.  For example:
exec Linked_Server.database.dbo.sp_executesql N'SELECT database.dbo.Function(@input)',N'@input int',@inp…

Delete Duplicate Rows in SQL Server 2005

A new addition to the DELETE command in SQL Server 2005 is the TOP statement. The DELETE TOP does the same thing as a SELECT TOP WHERE only the TOP number of rows are deleted. This can be very helpful when there are duplicate rows of data present.
DELETE TOP (1) FROM Sales.Customer WHERE CustomerID = 1


This would delete one of the duplicate rows for Customer number 1 Suppose somehow the whole customer table got duplicated. I duplicated the Sales.Customer table into a tmpCustomer table.


SELECT Top 1 CustomerID, COUNT(CustomerID) AS Cnt FROM tmpCustomer GROUP BY CustomerID HAVING COUNT(CustomerID) > 1 WHILE @@RowCount > 0 BEGIN DELETE Top (1) FROM tmpCustomer WHERE CustomerID = (SELECT Top (1) CustomerID FROM tmpCustomer GROUP BY CustomerID HAVING COUNT(CustomerID) > 1) END


While this worked just fine, it ran about 4 minutes for 38K rows. Let's try the dreaded CURSOR. Notic…

jQuery Image Swap with Effects

Swapping one image with another is probably one of the most used javascript techniques. Also Dreamweaver made “Image Replacement” even easier for non HTML/Javascript programmers by including this feature out of the box. One thing about Dreamweaver’s image swapping javascript is that it’s not the most beautiful javascript code. Well, as always with anything javascript related, jQuery is to the rescue. Query makes dynamic image swapping a peace of cake.
Firstly you have to copy the following javascript code in the HEAD section of your page. You can also save the following javascript functions in a seperate js file.


(function($) { $.fn.innerfade = function(options) { return this.each(function() { $.innerfade(this, options); }); }; $.innerfade = function(container, options) { var settings = { 'animationtype': 'fade', 'speed': 'fast', 'type': …

SQL Bulk Copy with C#.Net

Bulk copying of data from one data source to another data source is a new feature added to ADO.NET 2.0. Bulk copy classes provides the fastest way to transfer set of data from once source to the other. Each ADO.NET data provider provides bulk copy classes. For example, in SQL .NET data provider, the bulk copy operation is handled by SqlBulkCopy class, which is described in Figure 1. As you can see from Figure 1, data from a data source can be copied to one of the four types - DataReader, DataSet, DataTable, or XML.



Figure 1. Bulk Copy operation in ADO.NET 2.0
Using bulk copy operation, you can transfer data between two tables on the same SQL Server, between two different SQL Servers, or even two different types of database servers.





using System.Data.SqlClient; public static void CopyData(DataTable sourceTable, SqlConnection destConnection, SqlTransaction destTrans, string destTableName) { // new method: SQLBulkCopy: using (SqlBulkCopy s = new SqlBulkCopy(destConnec…

ASP.NET DropDownList with OptionGroup support

ASP.NET 2.0, for all its bells and whistles, lacks the odd bit of functionality for reasons completely unknown. One such notable omission is that of OptionGroup (<optgroup>) support in the DropDownList control. For those unfamiliar with the <optgroup> element, it is part of the XHTML standard, and has the effect of categorising items in a <select>, as the following image shows.

Control Adapters are new in ASP.NET 2.0, and allow the developer to override the rendering behavior of any control, very powerful stuff! Furthermore, Control Adapters are used in conjunction with a browser file, so specific browsers may be targeted, if required. Armed with that knowledge, the solution became simple. The attached download contains the requisite files to implement this solution in your own projects, but for posterity, I paste it here also.
public class DropDownListAdapter : System.Web.UI.WebControls.Adapters.WebControlAdapter { protected override void RenderContents(Ht…