Question

I’m trying to write if..else condition inside sql what I want to get the company name from “Company” table if their are companyID in companyID is NULL print “N/A” con someone help me

SELECT [contactID]
      ,[customerID]
      ,(SELECT Label.labelContactType FROM  Label WHERE Label.labelContactTypeID = Customer_Contacts.labelContactTypeID)AS Type
      ,[contactDetails]
      ,[status]
      ,[notes]
      ,CASE WHEN [Customer_Contacts].companyID = NULL THEN 'N/A'
        WHEN [Customer_Contacts].companyID  <> NULL THEN (SELECT [companyName]
        FROM [TaskManagementSystem_DB].[dbo].[Company] WHERE [Company].companyID = [Customer_Contacts].companyID)
        END AS Company

  FROM [TaskManagementSystem_DB].[dbo].[Customer_Contacts]

  WHERE customerID = 24

Answer 1

Why not just use a JOIN for this query:

SELECT cc.[contactID]
    ,cc.[customerID]
    ,l.labelContactType AS Type
    ,cc.[contactDetails]
    ,cc.[status]
    ,cc.[notes]
    , COALESCE(cp.[companyName], 'N/A') AS Company
FROM [TaskManagementSystem_DB].[dbo].[Customer_Contacts] cc
LEFT JOIN [TaskManagementSystem_DB].[dbo].[Company] cp
    on cc.companyID = cp.companyID
LEFT JOIN Label l
    on cc.labelContactTypeID = l.labelContactTypeID
WHERE cc.customerID = 24

If you need help with join syntax, here is a great visual explanation of joins