I'm trying to find number of rows for two tables:
Example 1 returns 81 (which is wrong).
SELECT p_id FROM j_posts
INNER JOIN j_blogs ON p_blog_id = b_id && b_approved = 1
WHERE p_is_draft = 0
UNION SELECT ep_id FROM j_external_posts
INNER JOIN j_blogs ON ep_blog_id = b_id && b_approved = 1
I have then tried to split up the query in two:
SELECT ep_id FROM j_external_posts INNER JOIN j_blogs ON ep_blog_id = b_id
&& b_approved = 1
First part of the query returns 70, and the second returns 39. This is the right amount of rows.
SELECT p_id FROM j_posts INNER JOIN j_blogs ON p_blog_id = b_id
&& b_approved = 1 WHERE p_is_draft = 0
What am I doing wrong in Example 1? It should return 109 instead of 81.
Thanks in advance
Use UNION ALL, UNION would return distinct rows
I think you must say "UNION ALL" instead of UNION.
UNION Does a implicit DISTINCT so same values are displayed only once..
Related
I am trying to find count of field by another field in same table on MySQL.My Table Like This:
Id DrgId CodeType IsPrincipal Code
182250051 48261836 I 1 T151
182250055 48261836 I 2 U739
182250059 48261836 I 3 Y929
182250061 48261836 I 4 W444
182250062 48261836 A 2 3006104
So I want to find used helper codes for T151 which is IsPrincipal equals 1.
Output should like this:
Code Helper_I_Count Helper_A_Count
T151 3 1
So I tried Like this:
SELECT t.`Code`,COUNT(v1.`Code`) AS EkTaniSay,COUNT(v2.`Code`) AS IslemSay
FROM TIGPatientCode t,
(
SELECT DRGPatientId,`Code`
FROM TIGPatientCode
WHERE IsPrincipal<>'1' AND CodeType='I'
) v1,
(
SELECT DRGPatientId,`Code`
FROM TIGPatientCode
WHERE IsPrincipal<>'1' AND CodeType='A'
) v2
WHERE t.IsPrincipal='1' AND t.DRGPatientId=v1.DRGPatientId AND t.DRGPatientId=v2.DRGPatientId
GROUP BY t.`Code`
But it wont get actual count.
How can I Do this?
Thanks
SELECT t2.Code,
SUM(t1.CodeType = 'I') AS EkTaniSay,
SUM(t1.CodeType = 'A') AS IslemSay
FROM TIGPatientCode AS t1
RIGHT JOIN TIGPatientCode AS t2 ON t1.DrgPatientId = t2.DrgPatientId
WHERE t1.isPrincipal != 1 AND t2.isPrincipal = 1
GROUP BY t1.DrgPatientId;
The first part of the query is based on multiple query same table but in different columns mysql. Then I join this with the table again to get the code for the principal row.
The problem with your query is that joining the two subqueries creates a cross-product of all the rows, which causes the counts to be multiplied. Also, if there's any group that doesn't have one of the codes, that subquery will return no rows, so the join will be empty for that code. You could fix the first problem by doing the counts in the subqueries rather than the main query. The second problem can be fixed by using LEFT JOIN. So the fixed version of your query would look like:
SELECT t.Code, v1.EkTaniSay, v2.IslemSay
FROM TIGPatientCode t
LEFT JOIN (
SELECT DRGPatientId, COUNT(*) AS EkTaniSay
FROM TIGPatientCode
WHERE IsPrincipal<>'1' AND CodeType='I'
GROUP BY DRGPatientId
) AS v2 ON t.DRGPatientId = v2.DRGPatientId
LEFT JOIN (
SELECT DRGPatientId, COUNT(*) AS IslemSay
FROM TIGPatientCode
WHERE IsPrincipal<>'1' AND CodeType='A'
GROUP BY DRGPatientId
) AS v1 ON t.DRGPatientId = v1.DRGPatientId
WHERE t.IsPrincipal = 1
DEMO
I have written a following query.
UPDATE
tbl_bookings tb
INNER JOIN
tbl_slots ts
ON ( tb.slot_id = ts.id )
SET tb.seat_freed = 1, ts.free_machines = ts.free_machines + 1
WHERE 1
AND tb.seat_freed = 0
AND tb.transactionComplete = 0
Here I am trying to free the seats by updating the seat_freed to 1 and increasing the free_machines counter by 1.
In case, there are more than 1 rows (say 3 rows) returned from tbl_bookings, I would want to increment the counter by .
Is there any way to do it, using the single. I can obviously do it by breaking it down into different queries, but single query is what I desire. :)
You could use a subquery with the exact same conditions to calculat the number of rows which will be affected by the update. I used DISTINCT for the count since i don't know how bookings and slots are related in your example.
UPDATE tbl_bookings tb
INNER JOIN tbl_slots ts ON ( tb.slot_id = ts.id )
INNER JOIN (SELECT count(DISTINCT b.id) seats_to_be_freed
FROM tbl_bookings b INNER JOIN tbl_slots s ON ( b.slot_id = s.id )
WHERE b.seat_freed=0 and b.transactionComplete=0) tmp
SET tb.seat_freed = 1, ts.free_machines = tmp.seats_to_be_freed
WHERE 1
AND tb.seat_freed = 0
AND tb.transactionComplete = 0
This MySQL statement give me all id_duel_player for player with id_player=30 and it work fine.
SELECT b.id_duel_player
FROM duels a
INNER JOIN duel_player b
ON a.id_duel = b.id_duel
WHERE id_player = 30
UNION ALL
SELECT c.id_duel_player
FROM duel_player c
INNER JOIN
(
SELECT aa.*
FROM duels aa
INNER JOIN duel_player bb
ON aa.id_duel = bb.id_duel
WHERE bb.id_player = 30
) d ON c.id_duel = d.id_duel AND c.id_player <> 30
I want to make MySQL statement for UPDATE (fields from duel_player table) all of this id_duel_player that returns this select statement.
UPDATE duel_player
SET num = 2,
total = 5
WHERE (duel_player.id_duel_player = id_duel_player's from above SELECT statement)
I want most effective and fastest way to do this.
Thanks
For 200-400 rows it's likely fastest to create a temporary table with the results, and then do the UPDATE with a join:
CREATE TEMPORARY TABLE id_duel_players AS
SELECT b.id_duel_player as id FROM duels a ...
UPDATE duel_player
JOIN id_duel_players ON duel_player.id_duel_player = id_duel_players.id
SET num = 2,
total = 5
For smaller result sets you may find the IN operator sufficiently fast (... WHERE id_duel_player IN (SELECT ...)), but I've found it unreliable for result sets with hundreds of rows. (Unreliable = suddenly no matches are found, no idea why, I haven't investigated.)
I have these tables:
single_user_has_university_has_course
single_user_users_id_user university_has_course_university_id_university university_has_course_course_id_course first_year_school last_year_school grade
1 1 1 2000 2001 15
And
university_has_course
university_id_university course_id_course
1 1 <<< I want to select this
15 1
1 3
15 3
The problem is that the query below return all rows where course_id_course = 1 but ignore theuniversity_id_university = 1`. Then, will return two rows.
query:
SELECT A.first_year_school, A.last_year_school, A.grade, U.university, C.course, T.type_course
FROM single_user_has_university_has_course A
INNER JOIN university_has_course Q
ON A.university_has_course_course_id_course = Q.course_id_course
INNER JOIN university U
ON Q.university_id_university = U.id_university
INNER JOIN course C
ON Q.course_id_course = C.id_course
INNER JOIN type_course T
ON C.type_course_id_type_course = T.id_type_course
AND A.single_user_users_id_user = ?
You are joining the last table to the previous joins on 2 constraints C.type_course_id_type_course = T.id_type_course AND A.single_user_users_id_user = ?. I think you want to write it as a WHERE clause. So replace your last line with:
WHERE A.single_user_users_id_user = ?
But you're not also trying to filter university_id_university = 1, so you may want to add it to the WHERE clause as well:
WHERE A.single_user_users_id_user = ? AND Q.university_id_university = ?
I'm stucked in this MYSQL SELECT:
SELECT episode.name
FROM tv.episode
JOIN tv.show ON episode.show_id = show.id
WHERE show.id = 73545
AND season_number = 4
AND episode.number =(SELECT MAX(number) FROM tv.episode WHERE season_number = 4)
Returns 0 rows
The return from the second select is 22, so it works.
Can you point me in the right direction?
Thanks!
You are not including WHERE show.id = 73545 in your subquery with the MAX.