SQL update from one Table to another based on a ID match

Question

I believe an UPDATE FROM with a JOIN will help:

MS SQL

UPDATE
    Sales_Import
SET
    Sales_Import.AccountNumber = RAN.AccountNumber
FROM
    Sales_Import SI
INNER JOIN
    RetrieveAccountNumber RAN
ON 
    SI.LeadID = RAN.LeadID;

MySQL and MariaDB

UPDATE
    Sales_Import SI,
    RetrieveAccountNumber RAN
SET
    SI.AccountNumber = RAN.AccountNumber
WHERE
    SI.LeadID = RAN.LeadID;

The simple Way to copy the content from one table to other is as follow:

UPDATE table2 
SET table2.col1 = table1.col1, 
table2.col2 = table1.col2,
...
FROM table1, table2 
WHERE table1.memberid = table2.memberid

You can also add the condition to get the particular data copied.

For SQL Server 2008 + Using MERGE rather than the proprietary UPDATE ... FROM syntax has some appeal.

As well as being standard SQL and thus more portable it also will raise an error in the event of there being multiple joined rows on the source side (and thus multiple possible different values to use in the update) rather than having the final result be undeterministic.

MERGE INTO Sales_Import
   USING RetrieveAccountNumber
      ON Sales_Import.LeadID = RetrieveAccountNumber.LeadID
WHEN MATCHED THEN
   UPDATE 
      SET AccountNumber = RetrieveAccountNumber.AccountNumber;

Unfortunately the choice of which to use may not come down purely to preferred style however. The implementation of MERGE in SQL Server has been afflicted with various bugs. Aaron Bertrand has compiled a list of the reported ones here.

Generic answer for future developers.

SQL Server

UPDATE 
     t1
SET 
     t1.column = t2.column
FROM 
     Table1 t1 
     INNER JOIN Table2 t2 
     ON t1.id = t2.id;

Oracle (and SQL Server)

UPDATE 
     t1
SET 
     t1.colmun = t2.column 
FROM 
     Table1 t1, 
     Table2 t2 
WHERE 
     t1.ID = t2.ID;

MySQL

UPDATE 
     Table1 t1, 
     Table2 t2
SET 
     t1.column = t2.column 
WHERE
     t1.ID = t2.ID;