UPDATE field from a matching

[sal21]

... i need a query to update the field DT in table A based the match SITO and SITO into the table B.
Update DT into table A with left, 4 of ID from &"-"& DIREZ...

For example sito = ag3 I need:

6788-dir
For example sito = dist I need:

3455-dir1

[HansV]

I'd create the update query in design view, and when it works correctly, switch to SQL view to inspect the SQL string that you need.