tsql - updating a table from a select statement

Question

I have two tables. TableA and TableB.
TableA holds a varbinary(max) column - named [BinaryA] TableB holds a column (named \"Volume\", type \"Long\") that contains each varbi

Answer 1

UPDATE tableB
SET    [volume] = (SELECT RetrieveAccountNumber.AccountNumber 
                          FROM   RetrieveAccountNumber 
                          WHERE  tableB.leadid =RetrieveAccountNumber.LeadID) 
WHERE Sales_Import.leadid = (SELECT  RetrieveAccountNumber.LeadID 
                             FROM   RetrieveAccountNumber 
                             WHERE  tableB.leadid = RetrieveAccountNumber.LeadID)

Answer 2

Try with this query:

UPDATE TableB 
SET TableB.[VOLUME] = DATALENGTH([T2.Binary])
FROM TableB
INNER JOIN [VAULT].[TABLEA] T2 ON TableB.TAL_ID = T2.TAL_ID

Assuming that TableB and [VAULT].[TABLEA] are related by ID field.