translations
+---------+----------------+----------+---------+
| id_user | id_translation | referrer | id_word |
+---------+----------------+----------+---------+
| 1 | 3 | NULL | 4 |
| 1 | 17 | NULL | 3 |
| 2 | 17 | NULL | 5 |
| 2 | 17 | NULL | 1 |
| 2 | 17 | NULL | 7 |
words
+----+------+
| id | word |
+----+------+
| 4 | out |
+----+------+
users_translations
+---------+----------------+----------+---------+
| id_user | id_translation | referrer | id_word |
+---------+----------------+----------+---------+
| 1 | 17 | 1 | 4 |
| 2 | 17 | 2 | 4 |
| 3 | 18 | NULL | 4 |
I need to select all translations for current word and id_translation, but if in the row referrer = 1 (current user), then I don't need another results (translations from another users for current word), if there is no referrer = 1, show all.
SELECT DISTINCT `t`.*, `ut`.`id_user` AS tuser
FROM translations AS t
LEFT JOIN users_translations AS ut ON `t`.`id` = `ut`.`id_translation`
INNER JOIN words ON `words`.`id` = `ut`.`id_word` OR `words`.`id` = `t`.`id_word`
WHERE (`word` = 'help')
ORDER BY `t`.`translation` ASC
+----+-------------+---------+---------+-------+
| id | translation | id_word | id_user | tuser |
+----+-------------+---------+---------+-------+
| 17 | допомагати | 4 | 1 | 2 |
| 17 | допомагати | 4 | 1 | 1 |
First row doesn't need, because we have tuser = 1. When there is no tuser = 1, all results should be returned.
I don't understand how to build select statement and I will be very appreciative that somebody shows me how to make it work.
First thing that comes to mind
--add this to your where clause
id_user <=
CASE WHEN EXISTS(SELECT * FROM translations WHERE id_user = 1 AND id_word = words.id_word)
THEN 1
ELSE (SELECT MAX(Id) FROM translations)
END
Related
I have a table like this:
+---------------+--------------+------+-----+----------+
| Field | Type | Null | Key | Default |
+---------------+--------------+------+-----+----------+
| id | smallint(6) | NO | PRI | NULL |
| Book | tinyint(4) | NO | | NULL |
| Chapter | smallint(6) | NO | | NULL |
| Paragraph | smallint(6) | NO | | NULL |
| Text | text | YES | | NULL |
| RevisionNum | mediumint(9) | NO | PRI | NULL |
+---------------+--------------+------+-----+----------+
mysql> select id,Book,Chapter,Paragraph,RevisionNum FROM MyTable ORDER BY id LIMIT 11;
+-----+------+---------+-----------+-------------+
| id | Book | Chapter | Paragraph | RevisionNum |
+-----+------+---------+-----------+-------------+
| 1 | 1 | 1 | 1 | 0 |
| 1 | 1 | 1 | 1 | 1 |
| 1 | 1 | 1 | 1 | 2 |
| 2 | 1 | 2 | 2 | 0 |
| 2 | 1 | 2 | 2 | 1 |
| 2 | 1 | 2 | 2 | 2 |
| 2 | 1 | 2 | 2 | 3 |
| 3 | 1 | 2 | 3 | 0 |
| 4 | 1 | 2 | 4 | 0 |
| 4 | 1 | 2 | 4 | 1 |
| 5 | 1 | 3 | 5 | 0 |
+-----+------+---------+-----------+-------------+
To find a book or chapter which has no unrevised paragraph,
I wish to query either the minimum value of the maximums of
all the distinct id's for that chapter or book, or else in
some fashion determine that no id remains unedited (with a
MAX(RevisionNum) of zero).
Most of my attempts to date have ended in errors like this one:
SELECT DISTINCT Book,RecordNum FROM MyTable
-> WHERE 0 < ALL (SELECT DISTINCT RecordNum,MAX(RevisionNum)
FROM MyTable
WHERE MAX(RevisionNum) > 0);
ERROR 1111 (HY000): Invalid use of group function
...And I wasn't using the "GROUP BY" function at all!
The following query produces results, but simply
gives ALL id's, and does not actually show a unique
set of Book records, as requested. How could this happen?
SELECT DISTINCT Book,id,MAX(RevisionNum) FROM MyTable GROUP BY id LIMIT 5;
+------+----+------------------+
| Book | id | MAX(RevisionNum) |
+------+----+------------------+
| 1 | 1 | 30 |
| 1 | 2 | 16 |
| 1 | 3 | 15 |
| 1 | 4 | 10 |
| 1 | 5 | 9 |
+------+----+------------------+
What would the correct query be to give results more like this:
+------+-----+-----------------------+
| Book | id | MIN(MAX(RevisionNum)) |
+------+-----+-----------------------+
| 1 | 5 | 3 |
| 2 | 17 | 1 |
| 3 | 33 | 2 |
| 4 | 147 | 0 |
| 5 | 225 | 2 |
+------+-----+-----------------------+
Are you looking for two levels of aggregation?
select id, book, min(max_revisionnum)
from (select id, book, chapter, paragraph, max(revisionnum) as max_revisionnum
from mytable
group by id, book, chapter, paragraph
) t
group by id, book;
EDIT:
Based on your comment, you can use:
select *
from (select id, book, chapter, paragraph, max(revisionnum) as max_revisionnum,
row_number() over (partition by book order by max(revisionnum) desc) as seqnum
from mytable
group by id, book, chapter, paragraph
) t
where seqnum = 1;
Here is a db<>fiddle.
In older versions of MariaDB, you can use a correlated subquery:
select t.*
from mytable t
where (id, book, chapter, paragraph, revisionnum) = (select t2.id, t2.book, t2.chapter, t2.paragraph, t2.revisionnum
from mytable t2
where t2.book = t.book
order by t2.revisionnum desc
limit 1
);
For this query, try adding an index on (book, revisionnum desc).
I have following schema:
+--+------+-----+----+
|id|device|token|cash|
+--+------+-----+----+
column device is unique and token is not unique and null by default.
What i want to achieve is to set all duplicate token values to default (null) leaving only one with highest cash. If duplicates have same cash leave first one.
I have heard about cursor, but it seems that it can be done with usual query.
I have tried following SELECT only to see if im right about my thought how to achieve this, but it seems im wrong.
SELECT
*
FROM
db.table
WHERE
db.table.token NOT IN (SELECT
*
FROM
(
SELECT DISTINCT
MAX(db.table.balance)
FROM
db.table
GROUP BY db.table.balance) temp
)
For example:
This table after query
+-----+---------+--------+-------+
| id | device | token | cash|
+-----+---------+--------+-------+
| 1 | dev_1 | tkn_1 | 3 |
| 2 | dev_2 | tkn_1 | 10 |
| 3 | dev_3 | tkn_2 | 10 |
| 4 | dev_4 | tkn_2 | 14 |
| 5 | dev_5 | tkn_3 | 10 |
| 6 | dev_6 | null | 10 |
| 7 | dev_7 | null | 10 |
| 8 | dev_8 | tkn_4 | 11 |
| 8 | dev_8 | tkn_4 | 11 |
| 8 | dev_8 | tkn_5 | 11 |
+-----+---------+--------+-------+
should be:
+-----+---------+--------+-------+
| id | device | token | cash|
+-----+---------+--------+-------+
| 1 | dev_1 | null | 3 |
| 2 | dev_2 | tkn_1 | 10 |
| 3 | dev_3 | null | 10 |
| 4 | dev_4 | tkn_2 | 14 |
| 5 | dev_5 | tkn_3 | 10 |
| 6 | dev_6 | null | 10 |
| 7 | dev_7 | null | 10 |
| 8 | dev_8 | tkn_4 | 11 |
| 8 | dev_8 | null | 11 |
| 8 | dev_8 | tkn_5 | 15 |
+-----+---------+--------+-------+
Thanks in advance :)
Try using an EXISTS subquery:
UPDATE yourTable t1
SET token = NULL
WHERE EXISTS (SELECT 1 FROM (SELECT * FROM yourTable) t2
WHERE t2.token = t1.token AND
t2.cash > t1.cash);
Demo
Note that this answer assumes that there would never be a tie for two token records having the same highest cash amount.
To set exactly one row in the even of duplicates on the maximum cash, use the id:
update t join
(select tt.*,
(select t3.id
from t t3
where t3.token = tt.token
order by t3.cash desc, id desc
) as max_cash_id
from t tt
) tt
on t.id = tt.id and t.id < tt.max_cash_id
set token = null;
Update: I want to use dynamic sql to select question as column and put answer in row, like cursor or loop, is that possible?
I want the select result like this
+--------+---------------+--------------------------------------------------------------------------+
| userid | Living Status | This is another question get from row and it's longer than 64 characters |
+--------+---------------+--------------------------------------------------------------------------+
| 19 | married | q2_opt3 |
+--------+---------------+--------------------------------------------------------------------------+
And here is my query
select
userid,
min(if(question.ordering=1,o.name,NULL )) as 'Living Status',
min(if(question.ordering=2,o.name,NULL )) as 'This is another question get from row and it's longer than 64 characters'
from answer
inner join question on question.key_value = answer.key_value
inner join q_option o on question.id = o.question_id and o.value = answer.answer
where userid in (19)
GROUP BY id
The question table is like
+----+----------+---------------------------------------------------------------------------+--------------+
| id | ordering | question | key_value |
+----+----------+---------------------------------------------------------------------------+--------------+
| 1 | 1 | Living Status | livingStatus |
| 2 | 2 | This is another question get from row and it's longer than 64 characters | question_2 |
+----+----------+---------------------------------------------------------------------------+--------------+
The answer table is like
+----+--------+--------------+--------+
| id | answer | key_value | userid |
+----+--------+--------------+--------+
| 1 | 2 | livingStatus | 19 |
| 2 | 3 | question_2 | 19 |
+----+--------+--------------+--------+
The q_option table is like
+----+----------+-------------+-------+
| id | name | question_id | value |
+----+----------+-------------+-------+
| 1 | single | 1 | 1 |
| 2 | married | 1 | 2 |
| 3 | divorced | 1 | 3 |
| 4 | q2_opt1 | 2 | 1 |
| 5 | q2_opt2 | 2 | 2 |
| 6 | q2_opt3 | 2 | 3 |
+----+----------+-------------+-------+
I have a question and answer website like stackoverflow. Here is the structure of some tables:
-- {superfluous} means some other columns which are not related to this question
// q&a
+----+-----------------+--------------------------+------+-----------+-----------+
| id | title | body | type | related | author_id |
+----+-----------------+--------------------------+------+-----------+-----------+
| 1 | How can I ... | I'm trying to make ... | q | NULL | 3 |
| 2 | | You can do that by ... | a | 1 | 1 |
| 3 | Why should I .. | I'm wonder, why ... | q | NULL | 1 |
| 4 | | First of all you ... | a | 1 | 2 |
| 5 | | Because that thing ... | a | 3 | 2 |
+----+-----------------+--------------------------+------+-----------+-----------+
// users
+----+--------+-----------------+
| id | name | {superfluous} |
+----+--------+-----------------+
| 1 | Jack | |
| 2 | Peter | |
| 3 | John | |
+----+--------+-----------------+
// votes
+----+----------+-----------+-------+-----------------+
| id | user_id | post_id | value | {superfluous} |
+----+----------+-----------+-------+-----------------+
| 1 | 3 | 4 | 1 | |
| 2 | 1 | 1 | -1 | |
| 3 | 2 | 1 | 1 | |
| 4 | 3 | 2 | -1 | |
| 5 | 1 | 4 | 1 | |
| 6 | 3 | 5 | -1 | |
+----+--------+-------------+-------+-----------------+
// tags
+----+------------+-----------------+
| id | name | {superfluous} |
+----+------------+-----------------+
| 1 | PHP | |
| 2 | SQL | |
| 3 | MySQL | |
| 4 | HTML | |
| 5 | CSS | |
| 6 | C# | |
+----+------------+-----------------+
// q&aTag
+-------+--------+
| q&aid | tag_id |
+-------+--------+
| 1 | 1 |
| 1 | 4 |
| 3 | 5 |
| 3 | 4 |
| 4 | 6 |
+-------+--------+
Now I need to find top users in a specific tag. For example, I need to find Peter as top user in PHP tag. Because his answer for question1 (which has PHP tag) has earned 2 upvotes. Is doing that possible?
Try this:
select q1.title, u.id, u.name, sum(v.value) total from `q&a` q1
left join `q&atag` qt ON q1.id = qt.`q&aid`
inner join tags t ON qt.tag_id = t.id
left join `q&a` q2 ON q2.related = q1.id
left join users u ON q2.author_id = u.id
left join votes v ON v.post_id = q2.id
where t.name = 'PHP'
group by q1.id, u.id
and here is a simple divided solution:
Let us divide it into sub queries:
get the id of the tag you will search for: select id from tags where name = 'PHP'
get the questions with this tag: select 'q&aid' from 'q&aTag' where tag_id = 1.
get the ids of answers for that question: select id, author_id fromq&awhere related in (2.)
get the final query: select user_id, sum(value) from votes where post_id in (3.) group by user_id
Now combining them all give the result:
select user_id, sum(`value`) total from votes
where post_id in (
select id from `q&a` where related in (
select `q&aid` from `q&aTag` where tag_id IN (
select id from tags where name = 'PHP'
)
)
)
group by user_id
you can add this at the end if you want only one record:
order by total desc limit 1
i try select all columns from two different tables WHERE active = 1
i have 2 tables table_pro and table_basic,
sql:"select * from table_basic,table.name";
and 2 condition:
WHERE active = 1
WHERE table_pro.id = table_basic.name.id
how to make it correctly
Here is table_pro
+----+--------+---------+-----------+
| id | people | rooms | active |
+----+--------+---------+-----------+
| 1 | 5 | 10 | 0 |
| 2 | 12 | 17 | 0 |
| 3 | 21 | 38 | 1 |
+----+--------+---------+-----------+
Here is table_basic
+---------+-------+---------+------------+----------+
| name_id | name | balance | title | time |
+---------+-------+---------+------------+----------+
| 1 |shop | 100 | failed | 15:10:20 |
| 2 |factory| 75 | error | 15:10:20 |
| 3 |studio | 25 | timed_out | 15:10:20 |
+---------+-------+---------+------------+----------+
I'd like to have this output result only rows (from of all columns) with status active = 1
+-----+-------+----- --+--------+-------+----------+---------+--------+
| id | people| rooms | name |balance| title | time | active |
+-----+-------+--------+--------+-------+----------+---------+--------+
| 3 | 21 | 38 | studio |25 | timed_out| 15:10:20| 1 |
+-----+-------+--------+--------+-------+----------+---------+--------+
Thanks
SELECT A.id, A.people, A.rooms, B.name, B.balance, B.title, B.time, A.active
FROM
table_pro AS A
JOIN
table_basic AS B
ON
A.id = B.name_id
WHERE
A.id = 3
SELECT table_pro.*, table_basic.*
FROM table_pro
INNER JOIN table_basic
ON table_basic.name_id = table_pro.id
WHERE table_pro.active = 1