sql server - Update column from another join column ,, -

first should easy db'es giving me pain here dont know why ,,

i have 2 tables , [table1] named applicationforms , [table2] named wfinstance need update formsubmitdate in table1 starteddate value in table 2 formsubmitdate null. write following query

update    applicationform set              formsubmitdate = wfi.startdate         applicationform app ,                       workflowinstances wfi      app.formsubmitdate null , wfi.applicationid = app.id  

when run query sql regenerate query one,,

update    applicationform set              formsubmitdate = wfi.startdate         applicationform app inner join                       workflowinstances wfi on app.id = wfi.applicationid cross join                       applicationform     (app.formsubmitdate null) 

i tried write statment using join ,,

update applicationform set formsubmitdate = wfi.startdate applicationform  join workflowinstances wfi on applicationform.id = wfi.applicationid   formsubmitdate null 

and sql generate same new syntax,,

now when run code , [all records] formsubmitdate fields filled first value of second table startdate. if have 1 record contains null value in table1

what missing here !?

i think want. try , let know.

update tabl3 set formsubmitdate=(select startdate   table4   table4.id=tabl3.id , tabl3.formsubmitdate null); 

another way write same thing be

update tabl3 set formsubmitdate= startdate table4 tabl3.id = table4.id , formsubmitdate null