Update table from another table in sql server

Here is the example to update table from another table where Empid is same and according some conditions.

We have to update 'tblEmpdetails' table
'Acno' as mention on second table 'tblEmpAcNo' with the condition that department must be 'Hr', Both table given bellow and updating query also given bellow.

Table 1 :- tblEmpDetails 
EmpId age Dep Acno
E1 20 IT 09876565
E2 30 Hr 75445678
E3 31 Hr 45674570
Table2 :- tblEmpAcNo
EmpId Acno
E1 02537565
E2 85245678
E3 41546456
E4 34074570
E5 45379200

UPDATE tblEmpDetails SET tblEmpDetails.AcNo = tblEmpAcNo.AcNo
FROM tblEmpAcNo
WHERE tblEmpDetails.EmpId = tblEmpAcNo.EmpId
AND tblEmpDetails.Dept = 'Hr'

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