I have a table. It has a pk of id and an index of [service, check, datetime].
id service check datetime score
---|-------|-------|----------|-----
1 | 1 | 4 |4/03/2009 | 399
2 | 2 | 4 |4/03/2009 | 522
3 | 1 | 5 |4/03/2009 | 244
4 | 2 | 5 |4/03/2009 | 555
5 | 1 | 4 |4/04/2009 | 111
6 | 2 | 4 |4/04/2009 | 322
7 | 1 | 5 |4/05/2009 | 455
8 | 2 | 5 |4/05/2009 | 675
Given a service 2 I need to select the rows for each unique check where it has the max date. So my result would look like this table.
id service check datetime score
---|-------|-------|----------|-----
6 | 2 | 4 |4/04/2009 | 322
8 | 2 | 5 |4/05/2009 | 675
Is there a short query for this? The best I have is this, but it returns too many checks. I just need the unique checks at it's latest datetime.
SELECT * FROM table where service=?;
First you need find out the biggest date for each check
SELECT `check`, MAX(`datetime`)
FROM YourTable
WHERE `service` = 2
GROUP BY `check`
Then join back to get the rest of the data.
SELECT Y.*
FROM YourTable Y
JOIN ( SELECT `check`, MAX(`datetime`) as m_date
FROM YourTable
WHERE `service` = 2
GROUP BY check) as `filter`
ON Y.`service` = `filter`.service
AND Y.`datetime` = `fiter`.m_date
WHERE Y.`service` = 2
Related
I have a table of routines. In this table, I have the column "grade" (which is not mandatory), and the column "date". Also, I have a number of days and an array of ids of users. I need a query that returns me the last routine that have a value != null for "grade" column and datediff(current_date,date) >= number_of_days for each id in the array and make an average of all these values.
e.g.
today = 2014/10/15
number_of_days = 10
ids(1,3)
routines
id | type | date | grade | user_id
1 | 1 | 2014-10-10 | 3 | 1
2 | 1 | 2014-10-04 | 3 | 1
3 | 1 | 2014-10-01 | 3 | 1
4 | 1 | 2014-09-24 | 2 | 1
5 | 1 | 2014-10-10 | 2 | 2
6 | 1 | 2014-10-04 | 3 | 2
7 | 1 | 2014-10-01 | 3 | 2
8 | 1 | 2014-09-24 | 1 | 2
9 | 1 | 2014-10-10 | 1 | 3
10 | 1 | 2014-10-04 | 1 | 3
11 | 1 | 2014-10-01 | 1 | 3
12 | 1 | 2014-09-24 | 1 | 3
In this case, my query would return an avg between "grade" of row id #2 and #10
I think you're saying that you want to consider rows having non-null values in the grade column, a date within a given number of days of the current date, and one of a given set of user_ids. Among those rows, for each user_id you want to choose the row with the latest date, and compute an average of the grade columns for those rows.
I will assume that you cannot have any two rows with the same user_id and date, both with non-null grades, else the question you want to ask does not have a well-defined answer.
A query along these lines should do the trick:
SELECT AVG(r.grade) AS average_grade
FROM
(SELECT user_id, MAX(date) AS date
FROM routines
WHERE grade IS NOT NULL
AND DATEDIFF(CURDATE(), date) >= 10
AND user_id IN (1,3)
GROUP BY user_id) AS md
JOIN routines r
ON r.user_id = md.user_id AND r.date = md.date
Note that in principle you need a grade IS NOT NULL condition on both the inner and the outer query to select the correct rows to average, but in practice AVG() ignores nulls, so you don't actually have to filter out the extra rows in the outer query.
I have a table (innoDB) that has 3 columns: ID, ID_FATHER, ROWPOS. ID is auto_increment and ROWPOS has values from other table. I need ID_FATHER to be incremented by 1 if ROWPOS is not a sequence, if it is a sequence ID_FATHER should not increment.
Like this:
ID | ID_FATHER | ROWPOS
1 | 1 | 250
2 | 2 | 253
3 | 2 | 254
4 | 3 | 260
5 | 4 | 263
6 | 5 | 268
7 | 6 | 270
8 | 6 | 271
9 | 6 | 272
10 | 7 | 276
Is there a way to do that?
With this query:
INSERT INTO mytable (i, rowpos)
SELECT #i := IF(t.rowpos = #prev_rowpos + 1, #i, #i + 1) AS i
, #prev_rowpos := t.rowpos AS rowpos
FROM temp
JOIN (SELECT #prev_rowpos := NULL, #i := 0) v
ORDER BY t.rowpos
I am able to import into the tables I want. But the problem is in the TABLE.Service, as you can see with this solution the ID_FATHER is wrong because it only increments by 1
but in this case it actually should be 2 because invoice 1 doesn't have service.
How can I solve this problem without changing all my schema.
TABLE.temp
ROW|TYPE |INVOICE_temp
1 |xxx |10
2 |xxP |led tv
3 |xxP |mp3 Player
4 |xxx |11
5 |xxP |tv cable
6 |xxS |install
xxx = Invoice number
xxP = Product
xxs = service
TABLE.Invoice_Number TABLE.Product
ID|ID_FATHER|ROWPOS|NUM ID|ID_FATHER|ROWPOS|PROD
1 | 1 | 1 | 10 1 | 1 | 2 | led tv
2 | 2 | 4 | 11 2 | 1 | 3 | mp3 player
3 | 2 | 5 | tv cable
TABLE.Service
ID|ID_FATHER|ROWPOS|SERV
1 | 1 | 6 | install
I made some changes in the query to work as I needed.
You could do something like this:
INSERT INTO mytable (i, rowpos)
SELECT #i := IF(t.rowpos = #prev_rowpos + 1, #i, #i + 1) AS i
, #prev_rowpos := t.rowpos AS rowpos
FROM another_table t
JOIN (SELECT #prev_rowpos := NULL, #i := 0) v
ORDER BY t.rowpos
(Test just the SELECT query, get that working returning the resultset you want, before you preface it with the INSERT.)
For completeness, I will add that this technique is dependent on UNDOCUMENTED and non-guaranteed behavior in MysQL, using "user variables". I've successfully used this approach many times, but for "one off" type admin functions, not ever embedded as SQL in an application.
Note that the ORDER of the expressions in the SELECT list is important, they are evaluated in the order they appear in the SELECT list. (MySQL doesn't guarantee this behavior, but we do observe it. It's important that the check of the user variables containing values from the previous row to precede the assignment of the current row values to the user variables. That's why i is returned first, followed by rowpos. If you reversed the order of those in the SELECT list, the query would operate differently, and we wouldn't get the same results.
The purpose of the inline view (aliased as v) is to initialize the user variables. Since MySQL materializes that view query into a "derived table" before the outer query runs, those variables get initialized before they are referenced in the outer query. We don't really care what the inline view query actually returns, except that we need it to return exactly one row (because we reference it in a JOIN operation to the table we really want to query).
E.g.:
DROP TABLE IF EXISTS my_table;
CREATE TABLE my_table
(id INT NOT NULL AUTO_INCREMENT PRIMARY KEY
,rowpos INT NOT NULL
);
INSERT INTO my_table (rowpos) VALUES
(250),
(253),
(254),
(260),
(263),
(268),
(270),
(271),
(272),
(276);
SELECT x.*
, #i:=#i+ISNULL(y.id) i
FROM my_table x
LEFT
JOIN my_table y
ON y.id < x.id
AND y.rowpos = x.rowpos - 1
, (SELECT #i:=0) vals
ORDER
BY x.id;
+----+--------+------+
| id | rowpos | i |
+----+--------+------+
| 1 | 250 | 1 |
| 2 | 253 | 2 |
| 3 | 254 | 2 |
| 4 | 260 | 3 |
| 5 | 263 | 4 |
| 6 | 268 | 5 |
| 7 | 270 | 6 |
| 8 | 271 | 6 |
| 9 | 272 | 6 |
| 10 | 276 | 7 |
+----+--------+------+
I have a table INVENTORY which consists of inventory items. I have the following table structure:
INSTALLATION_ID
COMPONENT_ID
HISTORY_ID
ON_STOCK
LAST_CHANGE
I need to obtain the row with the max HISTORY ID for records for which the spcified LAST_CHANGE month doesn't exist.
Each COMPONENT_ID and INSTALLATION_ID can occur multiple times, they are distinguished by their respective HISTORY_ID
Example:
I have the following records
COMPONENT_ID | INSTALLATION_ID | HISTORY_ID | LAST_CHANGE
1 | 100 | 1 | 2013-01-02
1 | 100 | 2 | 2013-02-01
1 | 100 | 3 | 2013-04-09
2 | 100 | 1 | 2013-02-22
2 | 100 | 2 | 2013-03-12
2 | 100 | 3 | 2013-07-07
2 | 100 | 4 | 2013-08-11
2 | 100 | 5 | 2013-09-15
2 | 100 | 6 | 2013-09-29
3 | 100 | 1 | 2013-02-14
3 | 100 | 2 | 2013-09-23
4 | 100 | 1 | 2013-04-17
I am now trying to retrieve the rows with the max HISTORY ID for each component but ONLY for COMPONENT_IDs in which the specifiec month does not exists
I have tried the following:
SELECT
INVENTORY.COMPONENT_ID,
INVENTORY.HISTORY_ID
FROM INVENTORY
WHERE INVENTORY.HISTORY_ID = (SELECT
MAX(t2.HISTORY_ID)
FROM INVENTORY t2
WHERE NOT EXISTS
(
SELECT *
FROM INVENTORY t3
WHERE MONTH(t3.LAST_CHANGE) = 9
AND YEAR(t3.LAST_CHANGE)= 2013
AND t3.HISTORY_ID = t2.HISTORY_ID
)
)
AND INVENTORY.INSTALLATION_ID = 200
AND YEAR(INVENTORY.LAST_CHANGE) = 2013
The query seems to have correct syntax but it times out.
In this particular case, i would like to retrieve the maximum HISTORY_ID for all components except for those that have records in September.
Because I need to completely exclude rows by their month, i cannot use NOT IN, since they will just suppress the records for september but the same component could show up with another month.
Could anybody give some pointers? Thanks a lot.
If I understand correctly what you want you can do it like this
SELECT component_id, MAX(history_id) history_id
FROM inventory
WHERE last_change BETWEEN '2013-01-01' AND '2013-12-31'
AND installation_id = 100
GROUP BY component_id
HAVING MAX(MONTH(last_change) = 9) = 0
Output:
| COMPONENT_ID | HISTORY_ID |
|--------------|------------|
| 1 | 3 |
| 4 | 1 |
If you always filter by installation_id and a year of last_change make sure that you have a compound index on (installation_id, last_change)
ALTER TABLE inventory ADD INDEX (installation_id, last_change);
Here is SQLFiddle demo
id | userid | total_points_spent
1 | 1 | 10
2 | 2 | 15
3 | 2 | 50
4 | 3 | 5
5 | 1 | 15
With the above table, I would first like to remove duplicates of userid keeping the rows with the largest total_points_spent, like so:
id | userid | total_points_spent
3 | 2 | 50
4 | 3 | 5
5 | 1 | 15
And then I would like to sum the values of total_points_spent, which would be the easy part, resulting in 70.
I am not really sure the "remove" you meant is to delete or to select. Here is the query for select only max totalpointspend record respectively.
SELECT tblA.*
FROM ( SELECT userid, MAX(totalpointspend) AS maxtotal
FROM tblA
GROUP BY userid ) AS dt
INNER JOIN tblA
ON tblA.userid = dt.userid
AND tblA.totalpointspend = dt.maxtotal
ORDER BY tblA.userid
I have one problem that I can't resolve.
I have 2 tables.
Table 1:
ID | Time
1 | 08:12:54
2 | 08:15:40
3 | 09:30:01
4 | 10:15:15
5 | 10:56:12
6 | 11:00:03
Table 2:
ID | Name| Previous | Current
1 | Queue | null | 11
2 | Queue | 11 | 19
3 | Queue | 19 | 11
3 | List | null | 11
4 | Queue | 11 | 16
4 | List | null | 11
5 | Queue | null | 15
6 | Queue | 15 | 19
The result wanted:
NumberQueue | Start | End
11 | 08:12:54 | 08:15:40
19 | 08:15:40 | 09:30:01
11 | 09:30:01 | 10:15:15
15 | 10:56:12 | 11:00:03
...
...
The previous and the current fields, have the number of the Queue and I want to know for each Queue, the start date and the end date, knowing that the previous has the previous Queue, and the current has the new Queue.
I want one query that can present this result. Help me. :(
Regards.
SELECT t1outer.ID, t1outer.Time AS start, (
SELECT Time FROM Table1 AS t1inner
WHERE t1inner.ID > t1outer.ID
ORDER BY ID ASC LIMIT 1
) AS end, Table2.Previous, Table2.Current
FROM Table1 AS t1outer
LEFT JOIN Table2 USING (ID);
This select statement should provide the information you need:
SELECT Current AS Number, t1out.Time AS Start, (
SELECT Time FROM Table1 AS t1in
WHERE t1in.ID > t1out.ID
ORDER BY ID ASC LIMIT 1
) AS End FROM Table2
LEFT JOIN Table1 AS t1out USING (ID)
WHERE Table2.Name = 'Queue';