I have a table in MySQL where all employees are listed. I have another where all employees are listed which have to work on a specific day. And now I want to select all employees which have free (or at least are NOT listed in the work-table).
In this fiddle you can see my schema.
A code like SELECT * FROM pf_mitarbeiter WHERE NOT LISTED AS employeeID IN pf_tagesplan_zuteilungen would be super awesome. But I take other versions as well too.
Thank you guys!
Use a LEFT JOIN to join pf_tagesplan_zuteilungen on employeeID with a condition that there's no rows matching pf_mitarbeiter:
SELECT t1.*
FROM pf_mitarbeiter t1
LEFT JOIN pf_tagesplan_zuteilungen t2 ON t2.employeeID = t1.ID AND t2.date = CURDATE()
WHERE t2.ID IS NULL
select *
from A
where not exists
(
select 1
from B
where a.key = b.key
)
Use a LEFT OUTER JOIN to join the two tables. By doing so, you can select all the rows from the pf_mitarbeiter table even though there is no related row in the pf_tagesplan_zuteilungen table.
SELECT
S.*
FROM
pf_mitarbeiter S
LEFT OUTER JOIN pf_tagesplan_zuteilungen T ON (S.ID = T.employeeID)
WHERE
T.ID IS NULL
;
The IS NULL condition restricts the join to only return pf_mitarbeiter rows where there is no pf_tagesplan_zuteilungen row with a matching employeeId.
Related
I have a table with a bunch of columns, but we only need to look at two of them. I'm trying to join another table on this table, but all we know about these two columns is that one will be null and the other won't:
client_id | note_id
The main table wants to join client_id (if not null) on clients.id OR note_id on notes.id if clients.id is null.
This will work for you. This is very basic query I wrote. Make changes if required.
SELECT * FROM YOUR_TABLE t
LEFT OUTER JOIN clients c ON t.client_id = c.id
LEFT OUTER JOIN notes n ON t.note_id = n.id
WHERE c.id IS NOT NULL OR n.id IS NOT NULL
Assuming there are 3 tables involved (the main table that contains client_id and note_id columns, clients table, and notes table), you can use a query such as this:
(select *
from mainTable inner join clients on mainTable.client_id = clients.id)
union
(select *
from mainTable inner join notes on mainTable.note_id = notes.id
where mainTable.client_id is NULL);
The above query contains 2 queries where each query will output rows where the joining column is not null. The results are then combined using union.
You can use coalesce in the join on clause. See demo here:
http://sqlfiddle.com/#!9/99911/2. If client id is null then use note id to join table1 and table2.
Select t1.client_id, t1.note_id,t2.client_id, t2.note_id
From table1 t1
Join table2 t2
on coalesce(t1.client_id, t1.note_id) =coalesce(t2.client_id, t2.note_id)
I have two tables,Table 1 and Table 2,Accid is the key to join two tables,
i want to sum revenueact and revenuutilz based on year and account, so out will look like this
in reality more data is there,when i join two tables and group by year only first account is coming,can anyone please help me on this?
You could try this:
SELECT
Accname,
YEAR,
SUM(revenueact) AS Revac,
SUM(revenuutilz) AS Revut
FROM table1 a
INNER JOIN Table2 b
ON a.Accid = b.Accid
GROUP BY Accname,Year
You cound use a join adn a group by
select t2.accname, sum(t1.revenueact), sum(t1.revenuutiliz), t1.year
from table1 t1
inner join table2 t2 on t1.accid = t2.accid
group by t2.accname, t1.year
Query 1:
SELECT sum(total_revenue_usd)
FROM table1 c
WHERE c.irt1_search_campaign_id IN (
SELECT assign_id
FROM table2 ga
LEFT JOIN table3 d
ON d.campaign_id = ga.assign_id
)
Query 2:
SELECT sum(total_revenue_usd)
FROM table1 c
LEFT JOIN table2 ga
ON c.irt1_search_campaign_id = ga.assign_id
LEFT JOIN table3 d
ON d.campaign_id = ga.assign_id
Query 1 gives me the correct result where as I need it in the second style without using 'in'. However Query 2 doesn't give the same result.
How can I change the first query without using 'in' ?
The reason being is that the small query is part of a much larger query, there are other conditions that won't work with 'in'
You could try something along the lines of
SELECT sum(total_revenue_usd)
FROM table1 c
JOIN
(
SELECT DISTINCT ga.assign_id
FROM table2 ga
JOIN table3 d
ON d.campaign_id = ga.assign_id
) x
ON c.irt1_search_campaign_id = x.assign_id
The queries do very different things:
The first query sums the total_revenue_usd from table1 where irt1_search_campaign_id exists in table2 as assign_id. (The outer join to table3 is absolutely unnecessary, by the way, because it doesn't change wether a table2.assign_id exists or not.) As you look for existence in table2, you can of course replace IN with EXISTS.
The second query gets you combinations of table1, table2 and table3. So, in case there are two records in table2 for an entry in table1 and three records in table3 for each of the two table2 records, you will get six records for the one table1 record. Thus you sum its total_revenue_usd sixfold. This is not what you want. Don't join table1 with the other tables.
EDIT: Here is the query using an exists clause. As mentioned, outer joining table3 doesn't alter the results.
Select sum(total_revenue_usd)
from table1 c
where exists
(
select *
from table2 ga
-- left join table3 d on d.campaign_id = ga.assign_id
where ga.assign_id = c.irt1_search_campaign_id
);
I wanna run a subquery that uses the value of the outer query in its where clause. Here's and example of what I wanna do:
SELECT * FROM `tbl1`
WHERE `tbl1`.`max_count` < (
SELECT COUNT(*) rc FROM `tbl2`
WHERE `tbl2`.`id` = `tbl1`.`id
)
There is tbl1 with a column named max_count, and there is tbl2 with rows referring to a row in tbl1(many-to-one relationship). What I wanna do is select rows in tbl1 where the number of rows in tbl2 referencing it is less than the max_count value of that row. But I'm pretty sure that what I wrote here, ain't gonna cut it. Any ideas?
Thanks a lot
try this -
SELECT * FROM `tbl1` t1
WHERE t1.`max_count` < (
SELECT COUNT(*) FROM `tbl2` t2
WHERE t2.`id` = t1.`id`
)
try using JOIN.
SELECT DISTINCT a.*
FROM tb1 a
INNER JOIN
(
SELECT id, COUNT(*) totalCount
FROM tbl2
GROUP BY id
) b ON a.ID = b.ID
WHERE a.max_count < b.totalCount
As an alternate solution, it's probably easier to just use a LEFT JOIN with HAVING than a subquery;
SELECT tbl1.*, COUNT(tbl2.id) current_count
FROM tbl1
LEFT JOIN tbl2
ON tbl1.id=tbl2.id
GROUP BY tbl1.id
HAVING COUNT(tbl2.id) < max_count
An SQLfiddle to test with.
Note that the GROUP BY in this case is a MySQL only thing, normally you'd need to GROUP BY every selected field in tbl1 even if tbl1.id is known to be unique per row.
Is it possible to get 1 result where I require data from 3 tables.
First table: I will need to grab all the fields (1 row found by a primary key)
Second table: I will need to grab the field 'username' (connected to first table by 'master_id')
Third table: I will need to grab the latest added row with the associated master_id key (table has 'date', 'master_id', 'previous_name').
select top 1 first.*, second.username, third.*
from first
inner join second on first.id = second.master_id
inner join third on first.id = third.master_id
order by
third.date desc
As always there are dozens of ways to skin a cat, I'm not sure if this is optimized as the subquery methods, but it should work.
You can join the three tables together. Then, you can use a "filter" join to keep only the latest Table3 row:
select *
from Table1 t1
join Table2 t2
on t2.master_id = t1.master_id
join Table3 t3
on t3.master_id = t1.master_id
join (
select master_id
, max(date) as max_date
from Table3
group by
master_id
) as filter
on t3.master_id = filter.master_id
and t3.date = filter.max_date
You'll need a correlated subquery for that third table.
SELECT t1.*, username, date, previous_name
FROM FirstTable t1
INNER JOIN SecondTable t2 ON t1.master_id=t2.master_id
INNER JOIN
(SELECT master_id, date, previous_name
FROM ThirdTable AS t3_1
WHERE date = (
SELECT MAX(date)
FROM ThirdTable AS t3_2
WHERE t3_2.master_id=t3_1.master_id)) q1 ON q1.master_id=t1.master_id;
NOTE: Untested.