I'm trying to update two columns in MySQL:
update table1
set (table1.score, table1.count) =
(select (table2.maxScore - table2.score ) as diff, count(*)
from table2
where (table2.maxScore - table2.score) <= 600
and table2.age > 50
group by diff);
But, MySQL does not support this syntax. I've seen some examples using JOIN, but I can't make it work here. Many thanks for any help!
Maybe you should SET their values separately,
UPDATE scoresUniverse
SET scoreUniver.GNfemScore = (Analytics.GN_recency_max_score - Analytics.GN_recency_score ),
ScoresUniverse.GNfemCount = (Select count(*) from Analytics.GN_recency_score where (Analytics.PR_recency_max_score - Analytics.PR_recency_score) <= 600 and Analytics.Older_female_50 > 0)
I figured it out! MySQL can definitely update more than one column at once. I needed to change my original query because MySQL requires using JOIN with ON when updating more than one column. To prove it, I added an extra column "secondCol" to my example. I have looked all over the web for this, and never found the answer. I hope this helps some people.
update table1 join
(select (table2.maxScore - table2.score ) as diff, count(*) as count
from table2
where (table2.maxScore - table2.score) <= 600
and table2.age > 50
group by diff) as scores
on table1.count = scores.count
set table1.score = scores.diff, table1.secondCol = scores.count;
Related
Below is my table called 'datapoints'. I am trying to retrieve instances where there are different instances of 'sensorValue' for the same 'timeOfReading' and 'sensorNumber'.
For example:
sensorNumber sensorValue timeOfReading
5 5 6
5 5 6
5 6 10 <----same time/sensor diff value!
5 7 10 <----same time/sensor diff value!
Should output: sensorNumber:5, timeOfReading: 10 as a result.
I understand this is a duplicate question, in fact I have one of the links provided below for references - however none of the solutions are working as my query simply never ends.
Below is my SQL code:
SELECT table1.sensorNumber, table1.timeOfReading
FROM datapoints table1
WHERE (SELECT COUNT(*)
FROM datapoints table2
WHERE table1.sensorNumber = table2.sensorNumber
AND table1.timeOfReading = table1.timeOfReading
AND table1.sensorValue != table2.sensorValue) > 1
AND table1.timeOfReading < 20;
Notice I have placed a bound for timeOfReading as low as 20. I also tried setting a bound for both table1 and table 2 as well but the query just runs until timeout without displaying results no matter what I put...
The database contains about 700mb of data, so I do not think I can just run this on the entire DB in a reasonable amount of time, I am wondering if this is the culprit?
If so how could I properly limit my query to run a search efficiently? If not what am doing wrong that this is not working?
Select rows having 2 columns equal value
EDIT:
Error Code: 2013. Lost connection to MySQL server during query 600.000 sec
When I try to run the query again I get this error unless I restart
Error Code: 2006. MySQL server has gone away 0.000 sec
You can use a self-JOIN to match related rows in the same table.
SELECT DISTINCT t1.sensorNumber, t1.timeOfReading
FROM datapoints AS t1
JOIN datapoints AS t2
ON t1.sensorNumber = t2.sensorNumber
AND t1.timeOfReading = t2.timeOfReading
AND t1.sensorValue != t2.sensorValue
WHERE t1.timeOfReading < 20
DEMO
To improve performance, make sure you have a composite index on sensorNumber and timeOfReading:
CREATE INDEX ix_sn_tr on datapoints (sensorNumber, timeOfReading);
I think you have missed a condition. Add a not condition also to retrieve only instances with different values.
SELECT *
FROM new_table a
WHERE EXISTS (SELECT * FROM new_table b
WHERE a.num = b.num
AND a.timeRead = b.timeRead
AND a.value != b.value);
you can try this query
select testTable.* from testTable inner join (
SELECT sensorNumber,timeOfReading
FROM testTable
group by sensorNumber , timeOfReading having Count(distinct sensorValue) > 1) t
on
t.sensorNumber = testTable.sensorNumber and t.timeOfReading = testTable.timeOfReading;
here is sqlFiddle
This query will return the sensorNumber and the timeOfReading where there are different values of sensorValue:
select sensorNumber, timeOfReading
from tablename
group by sensorNumber, timeOfReading
having count(distinct sensorValue)>1
and this will return the actual records:
select t.*
from
tablename t inner join (
select sensorNumber, timeOfReading
from tablename
group by sensorNumber, timeOfReading
having count(distinct sensorValue)>1
) d on t.sensorNumber=d.sensorNumber and t.timeOfReading=d.timeOfReading
I would suggest you to add an index on sensorNumber, timeOfReading
alter table tablename add index idx_sensor_time (sensorNumber, timeOfReading)
Modified some stuff from my pic so you guys can understand it
I have this database. I am trying to update a value from a table based on another value from an another table.
I want to update the SUM from salary like this :
( sum = presence * 5 )
This is what I've been trying to use ( unsuccessful )
update table salary
set suma.salary = users.presence * 5
FROM salary INNER JOIN users1 INNER JOIN presence on id_salary = id_presence
I am not sure what to do, I'd appreciate some help, Thanks
In MySQL to UPDATE tables with a join you use this syntax:
UPDATE table1, table2
SET table1.column = some expression
WHERE table1.column = table2.column
That said, even with the updated picture, in your SQL you are mentioning columns that I cannot understand in which table are to be found. You also have an inner join between salariu and users1, with no join condition. Could you please clean up the question and make everything clear?
Assuming you are making the updates to the db structure you were talking about, then you can start working on this one maybe:
UPDATE salary, presence
SET salary.sum = SUM(presence.hours) * 5
WHERE presence.id = salary.id
AND <some filter on the month that depends on salary.date>
Another way, but I'm not sure it is supported in all RDBMS, would be something like this:
UPDATE salary
SET sum = (
SELECT SUM(presence.hours) * 5
FROM user, presence
WHERE presence.id = salary.id
AND <some filter on the month that depends on salary.date>
)
I have a MySql table with a 'Order' field but when a record gets deleted a gap appears
how can i update my 'Order' field sequentially ?
If possible in one query 1 1
id.........order
1...........1
5...........2
4...........4
3...........6
5...........8
to
id.........order
1...........1
5...........2
4...........3
3...........4
5...........5
I could do this record by record
Getting a SELECT orderd by Order and row by row changing the Order field
but to be honest i don't like it.
thanks
Extra info :
I also would like to change it this way :
id.........order
1...........1
5...........2
4...........3
3...........3.5
5...........4
to
id.........order
1...........1
5...........2
4...........3
3...........4
5...........5
In MySQL you can do this:
update t join
(select t.*, (#rn := #rn + 1) as rn
from t cross join
(select #rn := 0) const
order by t.`order`
) torder
on t.id = torder.id
set `order` = torder.rn;
In most databases, you can also do this with a correlated subquery. But this might be a problem in MySQL because it doesn't allow the table being updated as a subquery:
update t
set `order` = (select count(*)
from t t2
where t2.`order` < t.`order` or
(t2.`order` = t.`order` and t2.id <= t.id)
);
There is no need to re-number or re-order. The table just gives you all your data. If you need it presented a certain way, that is the job of a query.
You don't even need to change the order value in the query either, just do:
SELECT * FROM MyTable WHERE mycolumn = 'MyCondition' ORDER BY order;
The above answer is excellent but it took me a while to grok it so I offer a slight rewrite which I hope brings clarity to others faster:
update
originalTable
join (select originalTable.ID,
(#newValue := #newValue + 10) as newValue
from originalTable
cross join (select #newValue := 0) newTable
order by originalTable.Sequence)
originalTable_reordered
on originalTable.ID = originalTable_reordered.ID
set originalTable.Sequence = originalTable_reordered.newValue;
Note that originalTable.* is NOT required - only the field used for the final join.
My example assumes the field to be updated is called Sequence (perhaps clearer in intent than order but mainly sidesteps the reserved keyword issue)
What took me a while to get was that "const" in the original answer was not a MySQL keyword. (I'm never a fan of abbreviations for that reason -- the can be interpreted many ways at times especially at these very when it is best they not be misinterpreted. Makes for verbose code I know but clarity always trumps convenience in my books.)
Not quite sure what the select #newValue := 0 is for but I think this is a side effect of having to express a variable before it can be used later on.
The value of this update is of course an atomic update to all the rows in question rather than doing a data pull and updating single rows one by one pragmatically.
My next question, which should not be difficult to ascertain, but I've learned that SQL can be a trick beast at the best of times, is to see if this can be safely done on a subset of data. (Where some originalTable.parentID is a set value).
What I'm attempting to do find values in a table which are less than the MAX of another field, minus a numeric value. Eg:
...WHERE some_table.value_1 = 0 AND another_table.value_2 <= (SELECT MAX(another_table.value_3) - 5) ORDER BY...
However, this is not working! My joins are all fine, and the query runs without the 2nd part of the WHERE statement, but if you'd like to see the rest of the code for more info, let me know!
Cheers!
Sparkles*
ps all the values are integers
Here is a working example using joins, try to apply it to yours:
SELECT *
FROM table1 t1
INNER JOIN table2 t2
ON t1.join_field = t2.join_field
WHERE t1.some_field = 1
AND t2.other_field <= (
SELECT (MAX(t22.third_field) - 5)
FROM table2 t22
);
If this is not exactly what you were looking for, please let me know and I will update it.
Use HAVING MAX(...)
Something like:
SELECT MIN(p.price) AS price, p.pricegroup
FROM articles_prices AS p
_YOUR_JOINED_TABLE_
WHERE p.articleID=10
GROUP BY p.pricegroup
HAVING MAX(p.price) > _VALUE_FROM_JOINED_TABLE_;
I have a table which has a field sort_id. In this field there are numbers from 1 to n, that define the order of the data sets.
Now I want to delete some elements and afterwards I want to reorder the table. Therefore I need a query that "finds" the gaps and changes the sort_id field according to the modifications.
Sure, I could do something like this:
SELECT sort_id FROM table WHERE id = 5
Then save the sort_id and afterwards:
DELETE FROM table WHERE id = 5
UPDATE table SET sort_id = sort_id - 1 WHERE sort_id > {id from above}
But I'd like to do the reordering process in one step.
Mladen and Arvo have good ideas, but unfortunately in MySQL you can't SELECT and UPDATE the same table in the same statement (even in a subquery). This is a known limitation of MySQL.
Here's a solution that uses MySQL user variables:
SET #i := 0;
UPDATE mytable
SET sort_id = (#i := #i + 1)
ORDER BY sort_id;
For what it's worth, I wouldn't bother doing this anyway. If your sort_id is used only for sorting and not as a kind of "row number," then the rows are still in sorted order after you delete the row where id=6. The values don't necessarily have to be consecutive for sorting.
for sql server 2005:
this is how you get the new sequence:
SELECT row_number() over(order by sort_id) as RN
FROM table
updating the table means you should join that select to your update:
update t1
set sort_id = t2.RN
FROM table t1
join (SELECT row_number() over(order by sort_id) as RN FROM table) t2
on t1.UniqueId = t2.UniqueId
I don't know MySQL syntax variations and cannot test query live, but something like next should give you at least an idea:
update table t1
set sort_id = (select count * from table t2 where t2.sort_id <= t1.sort_id)