Question

Here the
SQL FIDDLE and below tabel schema with values.
I want to select id_emp,fname_emp,TotalProject with a condition whose skillsid in (1,2).
Query i tried gives wrong output.

create table employee_emp(
id_emp int identity(1,1),fname_emp varchar(20),lname_emp varchar(20))
 insert into employee_emp values('John','Cena');
 insert into employee_emp values('Michel','shawn');
 insert into employee_emp values('Jay','mac');
 insert into employee_emp values('David','jackson');

create table skills_skl(
idemp_skl int,idskill_skl int
)
insert into skills_skl values(1,1);
insert into skills_skl values(1,2);
insert into skills_skl values(1,3);
insert into skills_skl values(1,4);
insert into skills_skl values(2,2);
insert into skills_skl values(2,3);
insert into skills_skl values(3,1);
insert into skills_skl values(3,4);
insert into skills_skl values(4,2);

create table employee_ejp(
id_ejp int identity(1,1),idemp_ejp int ,idproject_ejp int)
insert into employee_ejp values(1,1);
insert into employee_ejp values(1,2);
insert into employee_ejp values(1,3);
insert into employee_ejp values(2,3);
insert into employee_ejp values(2,2);
insert into employee_ejp values(3,1);
insert into employee_ejp values(4,4);

Query I tried

1)

select a.id_emp,a.fname_emp,count(b.id_ejp) TotalP from employee_emp a
join employee_ejp b on a.id_emp=b.idemp_ejp 
group by a.id_emp,a.fname_emp

2)

select a.id_emp,a.fname_emp,count(b.id_ejp) TotalP from employee_emp a
join employee_ejp b on a.id_emp=b.idemp_ejp join skills_skl c on c.idskill_skl=a.id_emp
where c.idskill_skl in (1,2)
group by a.id_emp,a.fname_emp

Answer 1

Here the easy approach:

;with emps_1_2 as (
select distinct a.id_emp
  from employee_emp a
  join skills_skl c on c.idemp_skl=a.id_emp     --Be carefull here!
  where c.idskill_skl in (1,2)
)  
select emp.id_emp,
       emp.fname_emp,
       coalesce( COUNT(ejp.id_ejp), 0) as TotalProject 
from       employee_emp emp 
inner join emps_1_2 emp12 
        on emp.id_emp = emp12.id_emp
 left join employee_ejp ejp 
        on emp.id_emp=ejp.idemp_ejp
group by emp.id_emp,emp.fname_emp

Results:

| ID_EMP | FNAME_EMP | TOTALPROJECT |
-------------------------------------
|      4 |     David |            1 |
|      3 |       Jay |            1 |
|      1 |      John |            3 |
|      2 |    Michel |            2 |