i've got a database similar to the following SqlFiddle http://sqlfiddle.com/#!9/f30a65/1/0
I need to obtain the group by but the trouble is that the data are on multiple columns...
Eg result expected:
VALUE - COUNT or Group By
13 - 2
11 - 1
Thanks to everyone
If you want to Group By on combine with all column you could use
SELECT value, count(value) as count FROM (
SELECT C1 as value FROM TABLE1
UNION ALL
SELECT C2 as value FROM TABLE1
UNION ALL
SELECT C3 as value FROM TABLE1
UNION ALL
SELECT C4 as value FROM TABLE1
UNION ALL
SELECT C5 as value FROM TABLE1
UNION ALL
SELECT C6 as value FROM TABLE1
) all_col GROUP BY value
Related
I have a MySQL table (below):
I can fetch the min or max of the column values simply but my problem is:
If any 3 or more fields value matched then fetch that value (if 3 fields values matched more than one value then the lowest of those values), for row #1 2100 will be the output and for row#3 55 will be the output.
If no field value matched with a minimum of 3 fields the lowest value of the entire row will be fetched, for row# 2 the output will be 1900.
I can use IF (e.g. select if(col1 = col2, col1, col2) from table) in select but I didn't find a solution for this situation. Can anyone help to write a MySQL query for this?
Thanks in advance!
You can use this query to get the results you want. It uses two nested subqueries: the first unpivots the data into a single column; the second then counts how many of each column value occur for a given ID value. The outer query then tests the maximum of the counts; if it is >= 3 then the minimum value which has a count of 3 or more is chosen, otherwise the minimum column value is chosen as the minimum column:
SELECT ID,
CASE WHEN MAX(cnt) >= 3 THEN MIN(CASE WHEN cnt >= 3 THEN col END)
ELSE MIN(col)
END AS min_col
FROM (
SELECT ID, col, COUNT(col) AS cnt
FROM (SELECT ID, col1 AS col FROM data
UNION ALL
SELECT ID, col2 FROM data
UNION ALL
SELECT ID, col3 FROM data
UNION ALL
SELECT ID, col4 FROM data
UNION ALL
SELECT ID, col5 FROM data
UNION ALL
SELECT ID, col6 FROM data
UNION ALL
SELECT ID, col7 FROM data
) d
GROUP BY ID, col
) dd
GROUP BY ID
Output (for your sample data):
ID min_col
1 2100
2 1900
3 55
Demo on SQLFiddle
I have a table like this
I want to check the all rows in Column A with column B and get the count of duplicates.
For example, I want to get the
count of 12 as 3(2 times in A+1 time in B)
count of 11 as 2(2 times in A+0 time in B)
count of 13 as 2(1 time in A+0 time in B)
How can I acheive it?
You can calculate the total occurrences from a union all. A where clause can show only the values that occur in the A column:
select nr
, count(*)
from (
select A as nr
from YourTable
union all
select B
from YourTable
) sub
where nr in -- only values that occur at least once in the A column
(
select A
from YourTable
)
group by
nr
having count(*) > 1 -- show only duplicates
You can combine all values in A and B then do the group by.
Then only select those values found in column A.
Select A, count(A) as cnt
From (
Select A
from yourTable
Union All
Select B
from yourTable) t
Where t.A in
(select distinct A from yourTable)
Group by t.A
Order by t.A;
Result:
A cnt
11 2
12 3
13 1
See demo: http://sqlfiddle.com/#!9/9fcfe9/3
I am facing a problem with MySQL query which is a variant of "Id for row with max value". I am either getting error or incorrect result for all my trials.
Here is the table structure
Row_id
Group_id
Grp_col1
Grp_col2
Field_for_aggregate_func
Another_field_for_row
For all rows with a particular group_id, I want to group by fields Grp_col1, Grp_col2 then get max value of Field_for_aggregate_func and then corresponding value of Another_field_for_row.
Query I have tried is like below
SELECT c.*
FROM mytable as c left outer join mytable as c1
on (
c.group_id=c1.group_id and
c.Grp_col1 = c1.Grp_col1 and
c.Grp_col2 = c1.Grp_col2 and
c.Field_for_aggregate_func > c1.Field_for_aggregate_func
)
where c.group_id=2
Among alternative solutions for this problem I want a high performance solution as this will be used for large set of data.
EDIT: Here is the sample set of row and expected answer
Group_ID Grp_col1 Grp_col2 Field_for_aggregate_func Another_field_for_row
2 -- N 12/31/2015 35
2 -- N 1/31/2016 15 select 15 from group for max value 1/31/2016
2 -- Y 12/31/2015 5
2 -- Y 1/1/2016 15
2 -- Y 1/2/2016 25
2 -- Y 1/3/2016 30 select 30 from group for max value 1/3/2016
You can use a sub-query to find the maximums, then join that with the original table, along the lines of:
select m1.group_id, m1.grp_col1, m1.grp_col2, m1.another_field_for_row, max_value
from mytable m1, (
select group_id, grp_col1, grp_col2, max(field_for_aggregate_func) as max_value
from mytable
group by group_id, grp_col1, grp_col2) as m2
where m1.group_id=m2.group_id
and m1.grp_col1=m2.grp_col1
and m1.grp_col2=m2.grp_col2
and m1.field_for_aggregate_func=m2.max_value;
Watch out for when there is more than one max_value for the given grouping. You'll get multiple rows for that grouping. Fiddle here.
Try this.
See Fiddle demo here
http://sqlfiddle.com/#!9/9a3c26/8
Select t1.* from table1 t1 inner join
(
Select a.group_id,a.grp_col2,
A.Field_for_aggregate_func,
count(*) as rnum from table1 a
Inner join table1 b
On a.group_id=b.group_id
And a.grp_col2=b.grp_col2
And a.Field_for_aggregate_func
<=b.Field_for_aggregate_func
Group by a.group_id,
a.grp_col2,
a.Field_for_aggregate_func) t2
On t1.group_id=t2.group_id
And t1.grp_col2=t2.grp_col2
And t1.Field_for_aggregate_func
=t2.Field_for_aggregate_func
And t2.rnum=1
Here first I am assigning a rownumber in descending order based on date. The selecting all the records for that date.
I am trying to display all records from table1 even if the catid not existing in table2 (all employee in table2 should have all catid from table1 with 0 days if not exising in table2) with the following sql query but getting an error
Error Code: 1054. Unknown column 'catid' in 'group statement'
select empid,days from table2 union select catid from
table1 group by empid, catid;
table1:
catid
1
2
3
table2:
empid catid days (computed column count(*))
1000 1 8
1000 3 10
expected result:
empid catid days
1000 1 8
1000 2 0 <---catid 2 and days 0 if catid not existing in table2 for empid 1000
1000 3 10
That is not the function of the union statement. Union statement does a set like capability which merging two sets. What you are looking for a is a join with the table 1 where you do a count and group by catid. Your data model to achieve this output itself is grievously wrong ;)
select employeeid, catid, sum(days) from table1, table2 group by employeeid, catid;
You just need a LEFT JOIN:
Select tab2.empid, tab2.catid, ifnull(tab2.days, 0)
from tab2
left join tab1 on tab2.catid = tab1.catid
Please note : While doing a UNION the number and type of the columns present in the first select should be the same as the next Selects.
So you need to first make the select columns in sync first.
can you check this and add empid similarly.
SELECT TABLE1.CATID, IFNULL(TABLE2.DAYS,0) FROM table1 LEFT OUTER JOIN
table2 ON table1.catid = table2.catid
Please use LEFT JOIN with IFNULL.
Select table2.empid, table1.catid, IFNULL(table2.days, 0) from table2
LEFT JOIN table1 ON table2.catid = table1.catid;
I have a table with an int valued column, which has values between 0 and 43 (both included).
I would like a query that returns the min value of the range [0,44) which is not in the table.
For example:
if the table contains: 3,5, 14. The query should return 0
if the table contains: 0,1, 14. The query should return 2
if the table contains: 0,3, 14. The query should return 1
If the table contains all values, the query should return empty.
How can I achieve that?
Since the value you want is either 0 or 1 greater than a value that exists in the table, you can just do;
SELECT MIN(value)
FROM (SELECT 0 value UNION SELECT value+1 FROM MyTable) a
WHERE value < 44 AND value NOT IN (SELECT value FROM MyTable)
An SQLfiddle to test with.
One way would be to create another table that contains the integers in [0,43] and then left join that and look for NULLs, the NULLs will tell you what values are missing.
Suppose you have:
create table numbers (n int not null);
and this table contains the integers from 0 to 43 (inclusive). If your table is t and has a column n which holds the numbers of interest, then:
select n.n
from numbers n left join t on n.n = t.n
where t.n is null
order by n.n
limit 1
should give you the result you're after.
This is a fairly common SQL technique when you're working with a sequence. The most common use is probably calendar tables.
One approach is to generate a set of 44 rows with integer values, and then perform an anti-join against the distinct set of values from the table, and the grab the mininum value.
SELECT MIN(r.val) AS min_val
FROM ( SELECT 0 AS val UNION ALL
SELECT 1 UNION ALL
SELECT 2 UNION ALL
SELECT 3 UNION ALL
SELECT 4 UNION ALL
SELECT 5 UNION ALL
-- ...
SELECT 44
) r
LEFT
JOIN ( SELECT t.int_valued_col
FROM mytable t
WHERE t.int_valued_col >= 0
AND t.int_valued_col <= 43
GROUP BY t.int_valued_col
) v
ON v.int_valued_col = r.col
WHERE v.int_valued_col IS NULL
A little bit hacky and MySQL-specific:
SELECT NULLIF(MAX(IF(val=#min, #min:=(val+1), #min)), #max) as min_empty
FROM (
SELECT DISTINCT val
FROM table1
-- WHERE val BETWEEN 0 AND 43
ORDER BY val) as vals, (SELECT #min:=0, #max:=44) as init;