I need some help to join my tables, I used 2 tables
//table news
id_news|title|
1 |first..|
2 |second..|
//table comment
id_comment|content|id_news
1|Haha..|1
2|Hahe..|2
3|Hoho..|1
I need an output use COUNT(*) comments in id_news 1
like
id_news|title|total_comment|
1|first..|**2**|
so far my syntax like
SELECT
news.id_news,
COUNT(distinct comment.id_news)
FROM
news
inner join comment ON (comment.id_news=news.id_news)
group by
news.id_news
I think you want:
SELECT news.id_news, COUNT(*)
FROM news INNER JOIN
comment
ON comment.id_news = news.id_news
GROUP BY news.id_news;
Note the following:
The select clause uses the same column as the group by
The COUNT() is not using a distinct. In your formulation, it would always return 1, regardless of the number of comments.
If you want news items with no comments, you would use a left outer join and change the count(*) to count(comment.id_news).
Try This Query you will get the data as you want :
SELECT
news.id_news,news.title,
(select count(*) from comment group_by id_news) as total_comment
FROM
news
inner join comment ON comment.id_news=news.id_news
Related
i have following sql in java project:
select distinct * from drivers inner join licenses on drivers.user_id=licenses.issuer_id
inner join users on drivers.user_id=users.id
where (licenses.state='ISSUED' or drivers.status='WAITING')
and users.is_deleted=false
And result i database looks like this:
And i would like to get only one result instead of two duplicated results.
How can i do that?
Solution 1 - That's Because one of data has duplicate value write distinct keyword with only column you want like this
Select distinct id, distinct creation_date, distinct modification_date from
YourTable
Solution 2 - apply distinct only on ID and once you get id you can get all data using in query
select * from yourtable where id in (select distinct id from drivers inner join
licenses
on drivers.user_id=licenses.issuer_id
inner join users on drivers.user_id=users.id
where (licenses.state='ISSUED' or drivers.status='WAITING')
and users.is_deleted=false )
Enum fields name on select, using COALESCE for fields which value is null.
usually you dont query distinct with * (all columns), because it means if one column has the same value but the rest isn't, it will be treated as a different rows. so you have to distinct only the column you want to, then get the data
I suspect that you want left joins like this:
select *
from users u left join
drivers d
on d.user_id = u.id and d.status = 'WAITING' left join
licenses l
on d.user_id = l.issuer_id and l.state = 'ISSUED'
where u.is_deleted = false and
(d.user_id is not null or l.issuer_id is not null);
Im trying to show all columns from my t1_elem table and join 2 columns in which I use COUNT.
I used query:
SELECT p.*,COUNT(t4_id) as ile_publikacji, COUNT(t7_id) as ile_fitow
FROM t1_elem p
LEFT OUTER JOIN t4_autorzy ON p.t1_id=t4_autorzy.t4_t1_id
LEFT JOIN t7_pliki ON p.t1_id=t7_pliki.t7_t1_id
GROUP BY t1_id
But the results are bad. What I'm doing wrong?
Probably you have multiple matches. As stated, the two counts will be the same. The simplest solution is probably to use distinct:
SELECT p.*, COUNT(DISTINCT t4_id) as ile_publikacji, COUNT(DISTINCT t7_id) as ile_fitow
FROM t1_elem p LEFT JOIn
t4_autorzy
ON p.t1_id = t4_autorzy.t4_t1_id LEFT JOIN
t7_pliki
ON p.t1_id=t7_pliki.t7_t1_id
GROUP BY t1_id
SELECT DISTINCT b.user_login
FROM wp_posts AS a JOIN wp_users AS b
WHERE a.post_author = b.ID AND a.post_type = 'tee';
This outputs what I need, it shows me the user's name.
However, I'd also like to COUNT how many times this occurred next to the user_login.
Help and explanation much appreciated.
You can do this with a GROUP BY and COUNT() aggregate:
Select b.user_login,
Count(*) As cnt
From wp_posts AS a
Join wp_users AS b On a.post_author = b.ID
Where a.post_type = 'tee'
Group By b.user_login;
It's also possible to use COUNT(DISTINCT [fieldname]). This will provide a count of unique non-null values present in [fieldname].
I have two tables in SQL Server, tbl_disputes and tbl_disputetypes. The tbl_disputes table contains a foreign key column disputetype. The table tbl_disputetypes contains the primary key field disputetypeid and disputetypedesc. The following query gives me a count of each disputetype from the tbl_disputes table.
select disputetype, count(disputetype) as numberof
from tbl_disputes
group by disputetype
What sort of join or subquery do I need to use to display the
tbl_disputetypes.dbo.disputetypedesc instead of tbl_disputes.dbo.disputetype?
EDIT Issue was because disputetypedesc was set as TEXT. I changed it to nvarchar, and the following query worked:
SELECT
tbl_disputetypes.disputetypedesc,
count(tbl_disputetypes.disputetypedesc)
FROM
tbl_disputes Left OUTER JOIN
tbl_disputetypes ON tbl_disputes.disputetype = tbl_disputetypes.disputetypeid
group by tbl_disputetypes.disputetypedesc
Unless I'm missing something, you can just LEFT JOIN the description:
select disputetypedesc, count(disputetype) as numberof
from tbl_disputes d
LEFT JOIN tbl_disputetypes dt
ON dt.disputetypeid = d.disputetype
group by disputetypedesc
Assuming 2005+:
WITH x(t, numberof) AS
(
SELECT disputetype, COUNT(*)
FROM tbl_disputes
GROUP BY disputetype
)
SELECT dt.disputetypedesc, x.numberof
FROM tbl_disputetypes AS dt
INNER JOIN x ON dt.disputetype = x.t;
A simple JOIN?
select
DT.disputetypedesc, count(*) as numberof
from
tbl_disputes D
JOIN
tbl_disputetypes DT ON D.disputetype = DT.disputetype
group by
DT.disputetypedesc
The basic idea is that you will need a sub-query. Something like this will work:
select disputetypedesc, disputetype, numberof
from (select disputetype, count(disputetype) numberof
from tbl_disputes
group by disputetype) t left outer join
tbl_disputetypes on t.disputetype = tbl_disputetypes.disputetype
I am not sure if I understand your question however you should be able to select all columns using a query similar to the code sample below.
The following query will join the two tables by the disputetypeid column. I changed the format of the SQL statement however you can obviously format it however you would like.
SELECT tbl_disputetypes.disputetypedesc
, tbl_disputes.*
, <any_column_from_either_table>
FROM tbl_disputes
INNER JOIN tbl_disputetypes
ON tbl_disputes.disputetypeid = tbl_disputetypes.disputetypeid
Hi all
Im having some problems combining data from 2 tables in to 1 query.
Now I have one table-nr1 with raw data of restaurants and in the other table-nr2 I have a number of restaurants that have been graded.
So, now I want to select all restaurants and at the same time select grades of that restaurant from table-nr2 and get the average value of those grades.
How can I do this in a single SQL query?
SELECT r.*,
COALESCE(
(
SELECT AVG(grade)
FROM table_nr2 g
WHERE g.restaurant_id = r.id
), 0)
FROM table-nr1 r
Assuming your restaurants have a name and id, and the your reviews have a grade
SELECT re.name, avg(ra.grade)
FROM table-nr1 re
LEFT JOIN table-nr2 ra ON re.id = ra.id
GROUP BY re.name
You need to group by all fields you want to select which are not aggregated, and left join means you will get all restaurants, irrespective of whether they have any ratings.
You need to perform a join. In this case an inner left join sounds fine, which is the default join. You can use USING syntax if the field that links them is the same on both sides, so you would end up with something like this:
SELECT table-nr1.*, AVG(table-nr2.score)
FROM table-nr1
JOIN table-nr2 USING (restrauntId)
Otherwise you could do something that links them using an on clause like this:
SELECT table-nr1.*, AVG(table-nr2.score)
FROM table-nr1
JOIN table-nr2 ON (table-nr1.restrauntId = table-nr2.restrauntId)