How to Compare two strings using a if in a stored procedure in sql server 2008?

Question

I want to do something like this:

declare @temp as varchar
    set @temp='Measure'

if(@temp == 'Measure')
   Select Measure from Measuretable
else
   Select OtherMeasure from Measuretable

Answer 1

declare @temp as varchar
  set @temp='Measure'
  if(@temp = 'Measure')
Select Measure from Measuretable
else
Select OtherMeasure from Measuretable

Answer 2

Two things:

1. Only need one (1) equals sign to evaluate
2. You need to specify a length on the VARCHAR - the default is a single character.

---

Use:

DECLARE @temp VARCHAR(10)
    SET @temp = 'm'

IF @temp = 'm'
  SELECT 'yes'
ELSE
  SELECT 'no'

VARCHAR(10) means the VARCHAR will accommodate up to 10 characters. More examples of the behavior -

DECLARE @temp VARCHAR
    SET @temp = 'm'

IF @temp = 'm'
  SELECT 'yes'
ELSE
  SELECT 'no'

...will return "yes"

DECLARE @temp VARCHAR
    SET @temp = 'mtest'

IF @temp = 'm'
  SELECT 'yes'
ELSE
  SELECT 'no'

...will return "no".

Answer 3

What you want is a SQL case statement. The form of these is either:

  select case [expression or column]
  when [value] then [result]
  when [value2] then [result2]
  else [value3] end

or:

  select case 
  when [expression or column] = [value] then [result]
  when [expression or column] = [value2] then [result2]
  else [value3] end

In your example you are after:

declare @temp as varchar(100)
set @temp='Measure'

select case @temp 
   when 'Measure' then Measure 
   else OtherMeasure end
from Measuretable