SUBSTRING in where clause

[maxamis4]

Hello folks,

I have the following substring statement I am using but I want to filter by my substring, can anyone help

 
SELECT     last_name, SUBSTRING(alternate_identifier, 5, 2) AS Contractor
FROM         ca_contact
WHERE     (contact_type = 2308) AND (inactive <> 1)
 
 

if i try this it fails with parsing errors

 
SELECT     last_name, SUBSTRING(alternate_identifier, 5, 2) AS Contractor
FROM         ca_contact
WHERE     (contact_type = 2308) AND (inactive <> 1) AND (Contractor = 'DC')
 
 

thanks!

[maxamis4]

I found it thank you all for looking into this. Here is the what I found. The alias unlike oracle can not be referenced in the where clause. So to perform the calculation you must reference the table.[field]name followed by the formula. See below for example:

SELECT     last_name, SUBSTRING(alternate_identifier, 5, 2) AS Contractor
FROM         ca_contact
WHERE     (SUBSTRING(alternate_identifier, 5, 2) = 'DC')