getting error The multi-part identifier "e.EpVisitCount" could not be bound. in sql server - sql

Question

I am working on converting mysql query to sql server, but when i run the query it gives me error The multi-part identifier "e.EpVisitCount" could not be bound. , here i have posted my both query can you please look into it, why it gives me error in sql server ?
Mysql Query(Working Fine) :
UPDATE
tb_EpVisitRange as v left JOIN tb_Episode as e ON (v.company_id = e.CustID) AND (v.CMW = e.CMW)
SET
e.EpVisitCount = If(PayerType='NonEp',0,If(LUPA=1,0,v.High)),
e.VisitAlert = If( e.TotVisits > v.High,1,NULL)
where UploadID = '23'
SQl Query(Getting Error) :
UPDATE v
SET
e.EpVisitCount = IIF(PayerType='NonEp',0,IIF(LUPA=1,0,v.High)),
e.VisitAlert = IIF( e.TotVisits > v.High,1,NULL)
FROM tb_EpVisitRange v
JOIN tb_Episode as e ON (v.company_id = e.CustID) AND (v.CMW = e.CMW)
where UploadID = '613'

Answer 1

You seem to want to update e rather than v. So, you might try:
UPDATE e
SET EpVisitCount = (CASE WHEN PayerType = 'NonEp' THEN 0
WHEN LUPA = 1 THEN 0
ELSE v.High
END),
VisitAlert = (CASE WHEN e.TotVisits > v.High THEN 1 END)
FROM tb_Episode e JOIN
tb_EpVisitRang v
ON v.company_id = e.CustID AND v.CMW = e.CMW
WHERE UploadID = '613';
Notes:
The problem appears to be the table alias used for the update.
SQL Server only allows updating one table in a statement. There is no need to qualify the column names for the SET.
Use CASE for conditions. It is the ANSI standard and supported by almost all database.
This is especially true for nested expressions. CASE supports multiple conditions.
You are updating e, so I made that the first table in the FROM clause. I find that logic easier to follow.
You should qualify UploadId.