Currently I use this query to show the differences:

SELECT 
    CASE
        WHEN PaymentMethodCRM <> PaymentMethodBOU THEN 'Payement Method CRM / BOU' 
        WHEN PaymentMethodCRM <> PaymentMethodFicheERP THEN 'Payement Method CRM / ERP'
        WHEN PaymentDeadlineCRM <> PaymentDeadlineBOU THEN 'Payment Deadline CRM / BOU'
        WHEN PaymentDeadlineCRM <> PaymentDeadlineFicheERP THEN 'Payment Deadline CRM / ERP'
        WHEN EditModeBOU <> EditModeContratERP THEN 'Edit Mode BOU / ERP'
        WHEN LTRIM(RTRIM(CompanyNameCRM)) <> LTRIM(RTRIM(CompanyNameBOU)) THEN 'Company Name CRM / BOU'
        WHEN LTRIM(RTRIM(CompanyNameBOU)) <> LTRIM(RTRIM(CAST(CompanyNameFicheERP AS NVARCHAR(50)))) THEN 'Company Name BOU / ERP'
        ELSE ''
    END AS Verification
FROM 
    Temp

But how to do if there are multiple differences?

My goal it’s to show it like this:

Payement Method CRM / BOU ; Payement Method CRM / ERP ; Payment Deadline CRM / ERP

I don’t want to have twenty lines of code to test each case

>Solution :

In SQL-Server 2016; You can do it using STUFF and FOR XML PATH.

SELECT STUFF((SELECT '; ' + DIFFERENCE 
              FROM (
                  SELECT 
                      CASE
                          WHEN PaymentMethodCRM <> PaymentMethodBOU THEN 'Payement Method CRM / BOU' 
                          WHEN PaymentMethodCRM <> PaymentMethodFicheERP THEN 'Payement Method CRM / ERP'
                          WHEN PaymentDeadlineCRM <> PaymentDeadlineBOU THEN 'Payment Deadline CRM / BOU'
                          WHEN PaymentDeadlineCRM <> PaymentDeadlineFicheERP THEN 'Payment Deadline CRM / ERP'
                          WHEN EditModeBOU <> EditModeContratERP THEN 'Edit Mode BOU / ERP'
                          WHEN LTRIM(RTRIM(CompanyNameCRM)) <> LTRIM(RTRIM(CompanyNameBOU)) THEN 'Company Name CRM / BOU'
                          WHEN LTRIM(RTRIM(CompanyNameBOU)) <> LTRIM(RTRIM(CAST(CompanyNameFicheERP AS NVARCHAR(50)))) THEN 'Company Name BOU / ERP'
                          ELSE ''
                      END AS DIFFERENCE
                  FROM 
                      Temp
                  ) AS DIFFERENCES_TABLE
              WHERE DIFFERENCE <> ''
              FOR XML PATH('')), 1, 2, '') AS DIFFERENCES;

In SQL-Server 2017; You can use STRING_AGG for the same.