Question

I have two tables ward1 and ward2ie;

create table ward1
(
ward_id int
)

create table ward2
(
ward_id int,
ward_name varchar(10)
)

and the values are —

insert into ward1 values(101);
insert into ward1 values(101);
insert into ward1 values(102);
insert into ward1 values(102);
insert into ward1 values(102);

insert into ward2 values(101,'child');
insert into ward2 values(102,'General');

So I need to produce total number of occurrence of ward_id.It was simple for me i used this code.

SELECT ward_id, count(ward_id) as "No of occurrence" from ward1 group by ward_id;

the output was —

ward_id   No of occurrence
101       2
102       3

this are the records from ward1 table, but when I want ward_name from the table ward2. I am getting error.
This is my code–

select ward1.ward_id as "ward_id",ward2.ward_name,
count(ward1.ward_id)as "No of occurrence" from ward1,
ward2 group by ward1.ward_id,ward2.ward_name 
having ward1.ward_id=ward2.ward_id;

It says not a group by expression…

I want to display like this–

ward_id   ward_name    No of occurrence
101       child        2
102       General      3

Please help….

Answer 1

Close. You really just need to join the 2 tables in a where clause (or using the preferred “join” statement)

select ward1.ward_id as "ward_id",ward2.ward_name,
count(ward1.ward_id)as "No of occurrence" 
from ward1,ward2 
where ward1.ward_id = ward2.ward_id
group by ward1.ward_id,ward2.ward_name;