I'm using MySql. I have a table with 2 column id (Primary Key) and id_of (Foreign Key). Number of id can have the same id_of. I want to get all the id and get the count of rows having the id_of related to the id. How to make this sql query/queries? So far I could only get this:
SELECT id, (SELECT COUNT(id_of) FROM test_table) AS count FROM test_table;
database's table:
id | id_of
----------------
abasb | 2131233
hdafd | 2131233
fajdf | 3546541
pogad | 3546541
afdaj | 2131233
fafda | 8661565
the results I want:
id | count
----------------
abasb | 3
hdafd | 3
fajdf | 2
pogad | 2
afdaj | 3
fafda | 1
just need a bit of correction your query
SELECT id,
(SELECT COUNT(*) FROM test_table t2 where t2.id_of=t1.id_of) AS count
FROM test_table t1
You may try this...
; with cte as ( select distinct id_of, count(*) as Coun from testtable )
select t.id , c.coun from testtable as t inner join cte as c on t.id_of=c.id_of
You can try this:
select id , count(*) over (partition by id_of) id_of from Yourtable
You could use ajoin on subqiery for count
select a.id, t.count_of_id_of
from test_table a
inner join (
select id_of, count(*) count_of_id_of
from test_table
group by id_of
) t on t.id_of= a.id_of
Related
I have a table like this in MYSQL:
ID | NAME | VALUE |
----------------------------
1 | Bob | 1 |
2 | Bob | 2 |
3 | Jack | 5 |
4 | Jack | 8 |
5 | Jack | 10 |
and I'm trying to update the VALUE column to the highest value of rows with same NAME. So the result should be:
ID | NAME | VALUE |
----------------------------
1 | Bob | 2 |
2 | Bob | 2 |
3 | Jack | 10 |
4 | Jack | 10 |
5 | Jack | 10 |
I managed to get the max value like this:
SELECT MAX(Value) max FROM `table` GROUP BY Name having count(*) >1 AND MAX(Value) != MIN(Value)
But can't figure out how to put it in my update
Update table set Value = (SELECT MAX(Value) max FROM `table` GROUP BY Name having count(*) >1 AND MAX(Value) != MIN(Value))
Doesn't work. I'd appreciate any help.
This is easier than other answers are making it.
UPDATE MyTable AS t1 INNER JOIN MyTable AS t2 USING (Name)
SET Value = GREATEST(t1.Value, t2.Value);
You don't have to find the largest value. You just have to join each row to the set of rows with the same name, and set the Value to the greater Value of the two joined rows. This is a no-op on some rows, but it will apply to every row in turn.
http://sqlfiddle.com/#!9/f79a3/1
UPDATE t1
INNER JOIN (SELECT name, MAX(`value`) max_value
FROM t1 GROUP BY name) t2
ON t1.name = t2.name
SET t1.value = t2.max_value;
Create a temporary table consisting of ID NAME and MAX VALUE as follows:
CREATE TEMP TABLE TABLE1 AS
(SELECT NAME,MAX(Value) value FROM `table` GROUP BY Name having count(*) >1
AND MAX(Value) != MIN(Value)
);
Use this temporary table to do your update as follows:
UPDATE
Table_A
SET
Table_A.value = Table_B.value
FROM
`table` AS Table_A
INNER JOIN TABLE1 AS Table_B
ON Table_A.NAME = Table_B.NAME
Also this code is somewhat of an approximation as i am not familiar with mysql but i am familiar with sql.
Let me know if this doesn't help.
Simple left join would do the trick.
Try this out and let me know in case of any queries.
select a.id,a.name,b.value
from
table a
left join
(select name,max(value) as value from table group by name) b
on a.name=b.name;
You may use this query. The table is joined with a subquery (table t2) that contains the results you want to update your table with:
UPDATE `table` t1,
(SELECT Name, MAX(Value) maxv, MIN(Value) minv
FROM `table`
GROUP BY Name
HAVING COUNT(*)>1 AND maxv != minv) t2
SET t1.Value = t2.maxv
WHERE t1.Name = t2.Name;
If you want to know how will the values be updated, you can first run an equivalent SELECT query:
SELECT t1.*, t2.maxv
FROM `table` t1,
(SELECT Name, MAX(Value) maxv, MIN(Value) minv
FROM `table`
GROUP BY Name
HAVING COUNT(*)>1 AND maxv != minv) t2
WHERE t1.Name = t2.Name;
This query will display all the fields of table, followed by the new value maxv. You can check the current value and the new value, and if it looks fine, you may run the UPDATE query.
I really don't know how to title this problem properly.
Heres the table structure:
ID | CLIENT_ID | …
ID is primary and auto increment. CLIENT_ID on the other hand can occur multiple times.
What i want is to fetch the rows by CLIENT_ID with highest ID ... Heres a example
ID | CLIENT_ID
1 | 1
2 | 1
3 | 2
4 | 3
5 | 2
So here CLIENT_ID 1 and 2 occurs multiple times (because there is a newer version).
After the query i want the following IDs in the results: 2,4,5 (Because the highest ID in rows with CLIENT_ID 1 is the row with ID 2 and so on)
If you need all the columns you can use a select in
select * from my_table
where (id, client_id) in ( select max(id), client_id
from my_table
group by client_id);
but if you need only the id
select id from my_table
where (id, client_id) in ( select max(id), client_id
from my_table
group by client_id);
or more simple
select max(id)
from my_table
group by client_id;
SELECT * FROM table GROUP BY client_id HAVING max(id)
this should be more efficient than a sub select
I have a table with user IDs split into 2 columns. (To explain this a little more, we capture the IDs of participants by scanning barcodes. Sometimes the barcode scanner function doesn't work for whatever reason, so we also allow manual entry of the ID, IF the barcode scanner doesn't work.) This results in data like the following:
+------+-----------+
| ID | ID_MANUAL |
+------+-----------+
| A | NULL |
| NULL | A |
| B | NULL |
| B | NULL |
| NULL | C |
| C | NULL |
| NULL | D |
| NULL | D |
+------+-----------+
I want to find all of the duplicate IDs, taking both columns into account. It's easy to find the duplicates that are only in 1 column ("B" and "D"). But how do I find the duplicates "A" and "C"? Ideally, the query would find and return ALL duplicates (A,B,C, and D).
Thanks!
Try this:
SELECT DUP.* FROM (SELECT ID FROM yourtable) ORI
LEFT JOIN yourtable DUP ON DUP.ID = ORI.ID_MANUAL WHERE DUP.ID IS NOT NULL
An advice: a field named ID m,ust be unique and not null. But if you have this structure, you can try this:
SELECT id
FROM yourtable t
WHERE id is not null
AND
(SELECT COUNT(*)
FROM yourtable t2
WHERE t2.id = t.id) +
(SELECT COUNT(*)
FROM yourtable t3
WHERE t3.id_manual = t.id) > 1
UNION
SELECT id_manual
FROM yourtable t
WHERE id_manual is not null
AND
(SELECT COUNT(*)
FROM yourtable t2
WHERE t2.id = t.id_manual) +
(SELECT COUNT(*)
FROM yourtable t3
WHERE t3.id_manual = t.id_manual) > 1
You can go on Sql Fiddle
You could try UNION ALL here:
select id,count(*)
from
(
select id
from yourtable
union all
select id_manual as id
from yourtable
) a
group by id
having count(*) >1;
try:
select id, count(*)
from
(
select id
from data
where id_manual is null
union all
select id_manual as id
from data
where id is null
) a
group by id
having count(*) > 1;
and
select id, id_manual
from data
group by id, id_manual
having count(*) > 1;
You can do this with a simple JOIN, using COALESCE and DISTINCT if you have a surrogate auto-increment primary key:
SELECT DISTINCT s2.pk, s2.ID, s2.ID_MANUAL
FROM scans s1
JOIN scans s2
ON COALESCE(s2.ID, s2.ID_MANUAL) = COALESCE(s1.ID, s1.ID_MANUAL)
AND s2.pk > s1.pk
This will exclude the original record, so you could delete the records returned in this result set.
Here's the SQL Fiddle.
Imagine the following MySQL table of orders:
id | name
1 | Mike
2 | Steve
3 | Janet
4 | Juliet
5 | Mike
6 | Jane
This is my current query:
SELECT * FROM table ORDER BY id DESC
However, I'd like to "group" those by name, so that I have orders from the same person listed after one another, however, I cannot do ORDER BY name.
This is my desired output:
id | name
6 | Jane
5 | Mike
1 | Mike
4 | Juliet
3 | Janet
2 | Steve
What's the query for this output?
E.g.:
SELECT y.id
, y.name
FROM my_table x
JOIN my_table y
ON y.name = x.name
GROUP
BY name
, id
ORDER
BY MAX(x.id) DESC
, id DESC;
You need to have special calculation to get their row position.
SELECT a.*
FROM tableName a
INNER JOIN
(
SELECT Name,
#ord := #ord + 1 ord
FROM
(
SELECT MAX(ID) ID, NAME
FROM TableName
GROUP BY Name
) a, (SELECT #ord := 0) b
ORDER BY ID DESC
) b ON a.Name = b.Name
ORDER BY b.ord, a.ID DESC
SQLFiddle Demo
You can do it via double ORDER BY:
SELECT * FROM t ORDER BY name ASC, id DESC
SELECT * FROM table1
ORDER BY field(NAME,'Mike','Jane') desc,
`ID` desc;
exactly as you asked
You could also try this query if you want to have something which is more generic SQL.
SELECT id, name
FROM ( SELECT id, name, (SELECT MAX(id) from Table1 where name=t.name) AS max_id
FROM Table1 AS t
ORDER BY max_id DESC, id DESC) as x
What about to use group by?
You can group it by name and then order...
Is it possible to select the next lower number from a table without using limit.
Eg: If my table had 10, 3, 2 , 1 I'm trying to select * from table where col > 10.
The result I'm expecting is 3. I know I can use limit 1, but can it be done without that?
Try
SELECT MAX(no) no
FROM table1
WHERE no < 10
Output:
| NO |
------
| 3 |
SQLFiddle
Try this query
SELECT
*
FROM
(SELECT
#rid:=#rid+1 as rId,
a.*
FROM
tbl a
JOIN
(SELECT #rid:=0) b
ORDER BY
id DESC)tmp
WHERE rId=2;
SQL FIDDLE:
| RID | ID | TYPE | DETAILS |
------------------------------------
| 2 | 28 | Twitter | #sqlfiddle5 |
Another approach
select a.* from supportContacts a inner join
(select max(id) as id
from supportContacts
where
id in (select id from supportContacts where id not in
(select max(id) from supportContacts)))b
on a.id=b.id
SQL FIDDLE:
| ID | TYPE | DETAILS |
------------------------------
| 28 | Twitter | #sqlfiddle5 |
Alternatively, this query will always get the second highest number based on the inner where clause.
SELECT *
FROM
(
SELECT t.col,
(
SELECT COUNT(distinct t2.col)
FROM tableName t2
WHERE t2.col >= t.col
) as rank
FROM tablename t
WHERE col <= 10
) xx
WHERE rank = 2 -- <<== means second highest
SQLFiddle Demo
SQLFiddle Demo (supports duplicate values)
If you want to get next lower number from table
you can get it with this query:
SELECT distinct col FROM table1 a
WHERE 2 = (SELECT count(DISTINCT(b.col)) FROM table1 b WHERE a.col >= b.col);
later again if you want to get third lower number you can just pass 3 in place of 2 in where clause
again if you want to get second higher number, just change the condition of where clause in inner query with
a.col <= b.col