I was thinking of subtracting digits one by one but didn't find a way to implement it after a big effort.
Row 1: 100211210
Row 2: 100010220
Result: 000201010
And the result has to be non-negative.
Select SUBSTR(t1.row,1,1)-(t2.row,1, 1)|| SUBSTR(t1.row,2,2)-SUBSTR(t2.row,2, 2)||... so on from table t1 where t1.row NOT IN (Select row in table t2);
This will check in the same table if the row exists then it will skip if not subtract digit by digit or you can use loop in pl/sql by declaring values for substr as i,j for both and then subtracting.
select GROUP_CONCAT(CAST(ABS(substring('123456782',c.count,1)-substring('323456789',c.count,1)) AS CHAR) separator '')
from (select c1.1*10+c2.1 count from (select 1 union all select 2 union all select 3 union all select 4 union all select 5 union all select 6 union all select 7 union all select 8 union all select 9 union all select 0) c1,
(select 1 union all select 2 union all select 3 union all select 4 union all select 5 union all select 6 union all select 7 union all select 8 union all select 9 union all select 0) c2 order by count) c
where c.count>0 and c.count<=length('123456782')
2 string is the same length, and the last parameter is the lenght of the strings
Related
I am working with MySQL and am trying to combine two Subqueries.
It is about time and excluding timespans.
The first (working) query fetches me every single valid day between two dates that are neigther saturday nor sunday (workdays):
SELECT * FROM
(SELECT adddate('1970-01-01',t4.i*10000 + t3.i*1000 + t2.i*100 + t1.i*10 + t0.i) selected_date from
(SELECT 0 i UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9) t0,
(SELECT 0 i UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9) t1,
(SELECT 0 i UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9) t2,
(SELECT 0 i UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9) t3,
(SELECT 0 i UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9) t4) v
WHERE selected_date BETWEEN '2021-04-01' and '2021-07-15'
AND weekday(selected_date) <> 5
AND weekday(selected_date) <> 6
The second query fetches me the start and end-Dates of vacations from a table (UNIX-Timestamps) and formats these dates the same way the first query returns them as 2 separate values (from, to):
SELECT date_format(FROM_UNIXTIME(from),'%Y-%m-%d') AS "from", date_format(FROM_UNIXTIME(to),'%Y-%m-%d') AS "to" FROM vacation
I am trying to eliminate every occurence of dates that are within these Timespans between 'from' and 'to' from my second query within my first query.
The thing that gets me is that i dont know how to set multiple BETWEENs dynamically to filter out those ranges. The second query returns multiple 'from' and 'to' values which i want to use as a "NOT BETWEEN-Filter" for my first query.
I hope what i said makes sense to you.
I am glad for every answer pushing me towards the right direction.
Thanks in advance
Felix
Use LEFT JOIN to join the two queries, and then a NULL check to exclude the matched rows.
SELECT t1.*
FROM (first query) AS t1
LEFT JOIN (second query) AS t2 ON t1.selected_date BETWEEN t2.from AND t2.to
WHERE t2.from IS NULL
It would also be better if the second query returned DATETIME values rather than formatted dates, so remove the calls to DATE_FORMAT().
Having a collection of publications, I want to assign a different release date for each one per author. For doing this I am subtracting to all the dates, from publication's date until yesterday, the already taken dates for that author.
The problem of this update is that the current record depends on the assignation of the previous one. Eg: if there is already a feature assigned to April 2nd, new features on that day will be pushed to the 3rd or beyond. But if there are two unassigned features April 2nd, they will be both assigned to the same day.
UPDATE publications pub
SET pub.release_date = (
SELECT all.Dates
FROM ( # This generates all dates between publication date until yesterday
SELECT curdate() - INTERVAL (a.a + (10 * b.a) + (100 * c.a) + (1000 * d.a) ) DAY as Dates
FROM (SELECT 0 as a UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6 UNION ALL SELECT 7 UNION ALL SELECT 8 UNION ALL SELECT 9) as a
CROSS JOIN (SELECT 0 as a UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6 UNION ALL SELECT 7 UNION ALL SELECT 8 UNION ALL SELECT 9) as b
CROSS JOIN (SELECT 0 as a UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6 UNION ALL SELECT 7 UNION ALL SELECT 8 UNION ALL SELECT 9) as c
CROSS JOIN (SELECT 0 as a UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6 UNION ALL SELECT 7 UNION ALL SELECT 8 UNION ALL SELECT 9) as d
) all
WHERE all.Dates > DATE(pub.date)
AND all.Dates < curdate()
AND all.Dates NOT IN ( # Already taken dates for this author
SELECT DISTINCT(DATE(taken.release_date))
FROM (SELECT * FROM publications) as taken
WHERE taken.author_id = pub.author_id
AND taken.release_date IS NOT NULL
)
ORDER BY Date ASC
limit 1
)
WHERE pub.release_date is null
AND pub.type = 'feature';
I read that the way SQL works (simplifying here) is fetching a dataset to the buffer, altering it and then storing. Guess MySQL does something similar. This mismatch seems to happen because the subquery is not reading from the data buffer that we are updating but from the original dataset.
MySQL doesn't allow PostgreSQL update syntax:
UPDATE ...
SET ...
FROM <-
WHERE ...;
Can a subquery inside a SQL update fetch rows which have just been updated?
Is there a simple way to compare a list of numbers in my query to a column in a table to return the ones that are NOT in the db?
I have a comma separated list of numbers (1,57, 888, 99, 76, 490, etc etc) that I need to compare to the number column in a table in my DB. SOME of those numbers are in the table, some are not. I need the query to return those that are in my comma separated list, but are NOT in the DB...
I would put the list of numbers to be checked in a table of their own, then use WHERE NOT EXISTS to check whether they exist in the table to be queried. See this SQLFiddle demo for an example of how this might be accomplished:
If you're comfortable with this syntax, you can even avoid putting into a temp table:
SELECT * FROM (
SELECT 1 AS mycolumn
UNION
SELECT 2
UNION
SELECT 3
UNION
SELECT 4
UNION
SELECT 5
UNION
SELECT 6
UNION
SELECT 7
) a
WHERE NOT EXISTS ( SELECT 1 FROM mytable b
WHERE b.mycolumn = a.mycolumn )
UPDATE per comments from OP
If you can insert your very long list of numbers into a table, then query as follows to get the numbers that are not found in the other table:
SELECT mynumber
FROM mytableof37000numbers a
WHERE NOT EXISTS ( SELECT 1 FROM myothertable b
WHERE b.othernumber = a.mynumber)
Alternately
SELECT mynumber
FROM mytableof37000numbers a
WHERE a.mynumber NOT IN ( SELECT b.othernumber FROM myothertable b )
Hope this helps.
May be this is what you are looking for.
Convert your CSV to rows using SUBSTRING_INDEX. Use NOT IN operator to find the values which is not present in DB
Then Convert the result back to CSV using Group_Concat.
select group_concat(value) from(
SELECT SUBSTRING_INDEX(SUBSTRING_INDEX(t.a, ',', n.n), ',', -1) value
FROM csv t CROSS JOIN
(
SELECT a.N + b.N * 10 + 1 n
FROM
(SELECT 0 AS N UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6 UNION ALL SELECT 7 UNION ALL SELECT 8 UNION ALL SELECT 9) a
,(SELECT 0 AS N UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6 UNION ALL SELECT 7 UNION ALL SELECT 8 UNION ALL SELECT 9) b
ORDER BY n
) n
WHERE n.n <= 1 + (LENGTH(t.a) - LENGTH(REPLACE(t.a, ',', '')))) ou
where value not in (select a from db)
SQLFIDDLE DEMO
CSV TO ROWS referred from this ANSWER
You could use the 'IN' clause of MySQL. Maybe check this out IN clause tutorial
I have a table witch has a field with the following record:
1,2,3,4,5,6
I would like to ask the following two things:
1) How can i make a foreign key in another table? The rule would be:
For any value seperated by comma in field `field_name` must be record of other_table.field_id
2) How can i do something like: SELECT explode(field) AS ex FROM table_name ?
the name's of row maybe can retrieve as ex[0]-->1, ex[1]-->2
While it is possible to do a join on a comma separated field (using FIND_IN_SET for example), I don't think there is a way to do this for a foreign key.
MySQL doesn't have an explode function, and your idea would seem to suggest a varying number of columns on each row.
You can split them onto different rows if necessary but it is ugly. And more a good reason to NOT use comma separated fields
SELECT DISTINCT SUBSTRING_INDEX(SUBSTRING_INDEX(field, ',', 1 + units.i + tens.i * 10 + hundreds.i * 100), ',', -1)
FROM table_name
CROSS JOIN (SELECT 0 AS i UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9) units
CROSS JOIN (SELECT 0 AS i UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9) tens
CROSS JOIN (SELECT 0 AS i UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9) hundreds
select id,name,total_copies from contacts.
that's the select statement. As is it can bring back
The result is
1,john,1
2,peter,3
3,sara,2
I need it to be
1,john,1
2,peter,2
2,peter,2
2,peter,2
3,sara,2
3,sara,2
So in a nutshell, if total_copies = 3 it must return the row 3 times, if value is 5 it must return row 5 times etc
You could use something like this:
SELECT contacts.*, n
FROM
(SELECT n1.n*10+n2.n n FROM
(SELECT 0 n UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3
UNION ALL SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6
UNION ALL SELECT 7 UNION ALL SELECT 8 UNION ALL SELECT 9) n1,
(SELECT 0 n UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3
UNION ALL SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6
UNION ALL SELECT 7 UNION ALL SELECT 8 UNION ALL SELECT 9) n2) numbers
INNER JOIN contacts ON contacts.total_copies>numbers.n
ORDER BY
id
Please see fiddle here. An indexed table with numbers should make the query easyer and faster:
CREATE TABLE numbers (n int);
INSERT INTO numbers VALUES (0), (1), (2), (3), (4), (5);
SELECT contacts.*
FROM numbers INNER JOIN contacts
ON contacts.total_copies>numbers.n
ORDER BY id;
Example here.