That could be accomplished with the following script:

IF EXISTS (

SELECT * FROM dbo.syscolumns WHERE id = (select id from dbo.sysobjects where type = ‘u’ and name = ‘Users‘) AND name = ‘RetailerId‘

)

The id of the RetailerId column is the same as the table’s id.

This file contains information about T-SQL variables (you know, the @@ variables)

1. When creating the table definition. For example:

CREATE TABLE [dbo].[Factura] (
[FacturaId] [char] (4) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL ,
[ExamenId] [int] NOT NULL UNIQUE,
[Fecha] [datetime] NOT NULL
)

2. After creating the table as follows:

CREATE TABLE [dbo].[Factura] (
[FacturaId] [char] (4) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL ,
[ExamenId] [int] NOT NULL ,
[Fecha] [datetime] NOT NULL
) ON [PRIMARY]

ALTER TABLE Factura
ADD UNIQUE (ExamenId)

3. Or, like this:

ALTER TABLE Factura
ADD CONSTRAINT UN_examenId UNIQUE (ExamenId)

In the first and second case SQL Server will create a deafult label for the unique column, for example something like UQ__Factura__29572725 .
In the third case we are explicitly applying the label UN_examenId for our unique column.

Apparently there’s another method to create a unique column, but I haven’t tested it. It’s as follows:

CREATE TABLE [dbo].[Factura] (
[FacturaId] [char] (4) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL ,
[ExamenId] [int] NOT NULL CONSTRAINT UN_Factura UNIQUE ,
[Fecha] [datetime] NOT NULL
) ON [PRIMARY]

use Northwind

SELECT c.CustomerId, c.CompanyName
FROM (Select * From Customers) c

We are creating a “memory” table and then selecting its data.

unitId
———–
183
184
187
188

and the table Transactions

unitId
———–
187
188
189
190

The following query:

SELECT ISNULL(p.unitId, t.unitId) as UnitId
FROM Packages p
FULL OUTER JOIN Transactions t ON p.unitId = t.unitId
WHERE p.unitId IS NULL OR t.unitId IS NULL

Will return this:

UnitId
———–
183
184
189
190

This is the negation of the intersection, just to say it somehow.

SELECT UnitCode, UnitName, UnitId, UnitParentId
INTO #ResultSet
FROM Units JOIN Parents ON (Units.UnitChildId = Parents.UnitId)
WHERE OrderId = 11 ORDER BY UnitParentId

Will create a temporal table named #ResultSet. This table will be available only on the session where it was created and as long as the session is active.

Response.Write("hello world")
Response.Redirect(”page2.asp”)

For some reason (an asp bug maybe) the redirect wont work.

But if we modify the code as follow:

Response.Redirect("page2.asp")
Response.Write(”hello world”)

Then it will work.

Edited: That’s not 100% true, sometimes it works, sometimes it doesn’t. In either case, if sometime you have a Redirect that is not working, you should keep this in mind.

When posting data to a page we are requesting that page, in other words, the page is requested.

default.asp

<form name=”employeeForm” method=”post” action=”page1.asp”>
<input name=”txtName” type=”text” value=”Bob” />
<input type=”submit” name=”btnOK” value=”OK” />
</form>

page1.asp

<%
‘ Response.Write(Request(”txtName”))

‘ name = Request.Form(”txtName”)
‘ name = Request(”txtName”)

‘ Response.Write(name)

Response.Write(”<br /> Request.Form(txtName) = ” & Request.Form(”txtName”))
Response.Write(”<br /> Request(txtName) = ” & Request(”txtName”))
%>

Both Request.Form(txtName) and Request(txtName) are the same.

page1.asp

<a href="page2.asp?myValue=Andee">Click me</a>

page2.asp

<%
‘ Dim queryStringValue

‘ queryStringValue = Request.QueryString(”myValue”)
‘ queryStringValue = Request(”myValue”)

Response.Write(”<br /> Request.QueryString(myValue) = ” & Request.QueryString(”myValue”))
Response.Write(”<br /> Request(myValue) = ” & Request(”myValue”))
%>

Both Request.QueryString() and Request() are the same