java - Missing Expression in UPDATE -

i'm required write couple of update queries parse data .csv file, not know how table works, don't have direct access database, got insert query 1 :

insert lr_umbrales_valores (umcod_id, uvfec_dt, uvval_nm) values ((select umcod_id lr_umbrales lrcod_nm = (     select lrcod_id lr_lineas_referencia     me_metrica_nm = ?     , fecha_baja_dt null)  , umtip_tx='s'), sysdate, ?) 

so i'm trying :

update lr_umbrales_valores set uvval_nm = ?  (     select umcod_id lr_umbrales      lrcod_nm = (         select lrcod_id lr_lineas_referencia          me_metrica_nm = ?          , fecha_baja_dt null     )      , umtip_tx = 's')  , uvfec_dt = to_date(?, 'dd/mm/yyyy hh24:mi:ss')"); 

this gives me 'missing expression' error (ora-00936)

this information tables got :

table need update (its uvval_nm)

one, umcod_id when lrcod_nm same lrcod_id next table.

lrcod_id when me_metrica_nm same '?' parameter

any tip in how approach this? needless say, i'm new sql may obvious mistake cannot right.

this part

where ( select umcod_id lr_umbrales  lrcod_nm = (     select lrcod_id lr_lineas_referencia      me_metrica_nm = ?      , fecha_baja_dt null )  , umtip_tx = 's')  

causes error. maybe wanted like

where umcod_id = (     select umcod_id lr_umbrales      lrcod_nm = (         select lrcod_id lr_lineas_referencia          me_metrica_nm = ?          , fecha_baja_dt null     )      , umtip_tx = 's')