create table emp
( emp_id   number,
  emp_name varchar2(20),
  salary   number
)

create table dept
(
 dept_id    number,
 emp_id     number,
 dept_name  varchar2(50),
 assigned_dtm_utc  date,
 estimated_dtm_utc date,
 assigned_dtm_local  date,
 estimated_dtm_local date
)

insert into emp values ( 1,'Ashok','50000')
insert into emp values ( 2,'Ram','60000')
insert into emp values ( 3,'krish','70000')
insert into emp values ( 4,'raj','80000')
insert into emp values ( 5,'mohan','90000')


insert into dept values ( 1,1,'IT',to_date(sysdate,'dd-mon-yyyy hh24:mi:ss'),to_date(sysdate,'dd-mon-yyyy hh24:mi:ss'),to_date(sysdate,'dd-mon-yyyy hh24:mi:ss'),
to_date(sysdate,'dd-mon-yyyy hh24:mi:ss'));
insert into dept values ( 2,2,'IT',to_date(sysdate,'dd-mon-yyyy hh24:mi:ss'),to_date(sysdate,'dd-mon-yyyy hh24:mi:ss'),to_date(sysdate,'dd-mon-yyyy hh24:mi:ss'),
to_date(sysdate,'dd-mon-yyyy hh24:mi:ss'));
insert into dept values ( 3,3,'IT',to_date(sysdate,'dd-mon-yyyy hh24:mi:ss'),to_date(sysdate,'dd-mon-yyyy hh24:mi:ss'),to_date(sysdate,'dd-mon-yyyy hh24:mi:ss'),
to_date(sysdate,'dd-mon-yyyy hh24:mi:ss'));

create or replace
procedure proc1 
(
i_flg varchar2,
i_flg1 varchar2,
i_date date
) 
AS

v_assigned_dtm_utc  varchar2(100)  :=  'assigned_dtm_utc' ;
v_estimated_dtm_utc   varchar2(100)  :=  'estimated_dtm_utc'   ;

v_assigned_dtm_local varchar2(100)  :=  'assigned_dtm_local' ;
v_estimated_dtm_local   varchar2(100)  :=  'estimated_dtm_local'   ;

v_assigned_dtm date;
v_estimated_dtm date;




v_flg  varchar2(1);
v_flg1 varchar2(1);

v_date date;
v_empid number ;
v_exact_match varchar2(1) ;

--i_date date := sysdate ;


Begin

 if ( i_flg  = 'D') and ( i_flg1 = 'L' ) then

             v_assigned_dtm   := v_assigned_dtm_local   ;
             v_estimated_dtm  := v_estimated_dtm_local     ;
             v_date           := i_date          ;
            
 elsif ( i_flg  = 'D') and ( i_flg1 = 'U' )   then
 
             v_assigned_dtm := v_assigned_dtm_utc     ;
             v_estimated_dtm   := v_estimated_dtm_utc       ;
             v_date      := i_date          ;
End if ;

select b.emp_id,
        decode(
 decode( trunc(v_assigned_dtm), TRUNC(i_date),'Y','N'),'Y','Y',
 decode( trunc(v_estimated_dtm), TRUNC(i_date),'Y','N'),'N'
       ) exact_match
       into v_empid, v_exact_match
from  emp b, dept a 
where 
B.emp_id = a.dept_id and
(TRUNC(v_assigned_dtm) = TRUNC(i_date) OR
 TRUNC(v_estimated_dtm) = TRUNC(i_date)) ;
 
 
End proc1;


Can i assign variables at left hand side on WHERE class?

i will post my errors shortly

Error(49,10): PL/SQL: ORA-00932: inconsistent datatypes: expected DATE got NUMBER

trunc(v_estimated_dtm

v_assigned_dtm   := v_assigned_dtm_local   ;

create or replace
procedure proc1 
(
i_flg varchar2,
i_flg1 varchar2,
i_date date
) 
AS

v_assigned_dtm_utc  varchar2(100)  :=  'assigned_dtm_utc' ;
v_estimated_dtm_utc   varchar2(100)  :=  'estimated_dtm_utc'   ;

v_assigned_dtm_local varchar2(100)  :=  'assigned_dtm_local' ;
v_estimated_dtm_local   varchar2(100)  :=  'estimated_dtm_local'   ;

v_assigned_dtm varchar2(100);
v_estimated_dtm varchar2(100);

v_flg  varchar2(1);
v_flg1 varchar2(1);

v_date date;
v_empid number ;
v_exact_match varchar2(1) ;

--i_date date := sysdate ;


Begin

 if ( i_flg  = 'D') and ( i_flg1 = 'L' ) then

             v_assigned_dtm   := v_assigned_dtm_local   ;
             v_estimated_dtm  := v_estimated_dtm_local     ;
             v_date           := i_date          ;
            
 elsif ( i_flg  = 'D') and ( i_flg1 = 'U' )   then
 
             v_assigned_dtm := v_assigned_dtm_utc     ;
             v_estimated_dtm   := v_estimated_dtm_utc       ;
             v_date      := i_date          ;
End if ;

select b.emp_id,
        decode(
 decode( trunc(v_assigned_dtm), TRUNC(i_date),'Y','N'),'Y','Y',
 decode( trunc(v_estimated_dtm), TRUNC(i_date),'Y','N'),'N'
       ) exact_match
       into v_empid, v_exact_match
from  emp b, dept a 
where 
B.emp_id = a.dept_id and
(TRUNC(v_assigned_dtm) = TRUNC(i_date) OR
 TRUNC(v_estimated_dtm) = TRUNC(i_date)) ;
 
 
End proc1;

with temp_table_with_comp_dates as
  ( select case when i_flg  = 'D' and i_flg1 = 'L' then assigned_dtm_local
                when i_flg  = 'D' and i_flg1 = 'U' then assigned_dtm_utc
           end assigned_dtm,
           case when i_flg  = 'D' and i_flg1 = 'L' then estimated_dtm_local
                when i_flg  = 'D' and i_flg1 = 'U' then estimated_dtm_utc
           end estimated_dtm,
           <whichever other columns used>
    from <the table containing these DATE columns> )
select <use assigned_dtm and estimated_dtm instead those variables>
  into v_empid, v_exact_match
from help_table_with_comp_dates, <other table(s) not included above>
where <join and filtering conditions; again use use assigned_dtm and estimated_dtm>;