I would like to request a table which looks like this:
Table1
record
element
value
62
56
637689
62
163
12/1990
...
joined with another table:
Table2
user_id
record
64
62
expecting this result: 637689,"12/1990" based on user_id=64 (not implemented in my request as i am unable to write the correct JOIN syntax
i tried with this request:
SELECT record,
(CASE WHEN element = 163 THEN value END) AS numserie,
(CASE WHEN element = 56 THEN value END) AS dateprod
FROM Table1
GROUP BY record
ORDER BY record DESC;
, but in heidiSQL, i have this result
numserie
dateprod
637689
NULL
i tried on others "element" number, always NULL
i tried to swap the two CASE lines, the result swap either
What is wrong ?
You need to aggregate the CASE expressions. Using the MAX function is one option:
SELECT
record,
MAX(CASE WHEN element = 163 THEN value END) AS numserie,
MAX(CASE WHEN element = 56 THEN value END) AS dateprod
FROM Table1
GROUP BY record
ORDER BY record DESC;
Related
I have the following table structure:
name
value
success
name 1
10
0
name 2
20
0
name 2
30
1
And my query is:
SELECT name, SUM(value) as valueTotal FROM TableName GROUP BY name
The result is:
name
valueTotal
name 1
10
name 2
50
Now I want to add a new column which will contain the sum of only successful rows. But if I add this condition, it will apply to all selected fields:
SELECT name, SUM(value) as valueTotal, SUM(value) as successValueTotal FROM TableName WHERE success = 1 GROUP BY name
Here is the result I want to get:
name
valueTotal
successValueTotal
name 1
10
0
name 2
50
30
How can I add a field with a separate condition that does not affect the main query? Thx)
You can use the SUM function with a conditional aggregation on whether success is 1 or not. When success is 1, then take the value of the value field, otherwise sum up 0.
SELECT name,
SUM(value) AS valueTotal,
SUM(IF(success = 1, value, 0)) AS successValueTotal
FROM TableName
GROUP BY name
Try it here.
This is the typical use case for CASE WHEN:
SELECT name,
SUM(value) AS valueTotal,
SUM(CASE WHEN success = 1 THEN value ELSE 0 END) AS successValueTotal
FROM TableName
GROUP BY name
You can (like lemon showed) also use an if clause in MYSQL. This is a bit shorter, but the query will not work on every DB while CASE WHEN does. So I think both is fine.
I have requirement like as below.
Need a MYSQL query to replace value with maching the below condition.
i have a table containg the Product ID
Product_ID
1
2
3
4
5
15
25
I want to replace the 5 with value of 1.111. My requiremnet is this that it should only replace the 5 value not the 15 value.
example 5 should be 1.111 but it sould not replace the 15 value.
You can use IF() or CASE to select a different value when the value meets a condition.
SELECT IF(product_id = '5', '1.111', product_id)
FROM yourTable
or
SELECT CASE product_id
WHEN '5' THEN '1.111'
ELSE product_id
END
FROM yourTable
CASE generalizes more easily to other values that you want to replace, since you can have multiple WHEN clauses.
I have a table like this
execution_plan_id test_case_name results
37 LandingPage.test SKIPPED
38 LandingPage.test SKIPPED
table image
I want a query which will show the results in below format.
test_case_name results for 37 result for 38
LandingPage.test SKIPPED SKIPPED
The problem is, there can be multiple rows with different execution_plan_id. So i want a query which will dynamically create a column. Also i will pass execution_plan_id in where clause
select test_case_name,
max(case when execution_plan_id = 37 then results end) result_37,
max(case when execution_plan_id = 38 then results end) result_38
from my_table
group by test_case_name;
I have tried searching all over for answers but none have answered my exact issue. I have what should be a relatively simple query. However, I am very new and still learning SQL.
I need to query two columns with different dates. I want to return rows with the current number of accounts and current outstanding balance and in the same query, return rows for the same columns with data 90 days prior. This way, we can see how much the number of accounts and balance increased over the past 90 days. Optimally, I am looking for results like this:
PropCode|PropCat|Accts|AcctBal|PriorAccts|PriorBal|
----------------------------------------------------
77 |Comm | 350 | 1,000| 275 | 750
Below is my starting query. I realize it's completely wrong but I have tried numerous different solution attempts but none seem to work for my specific problem. I included it to give an idea of my needs. The accts & AcctBal columns would contain the 1/31/14 data. The PriorAcct & PriorBal columns would contain the 10/31/13 data.
select
prop_code AS PropCode,
prop_cat,
COUNT(act_num) Accts,
SUM(act_bal) AcctBal,
(SELECT
COUNT(act_num)
FROM table1
where date = '10/31/13'
and Pro_Group in ('BB','FF')
and prop_cat not in ('retail', 'personal')
and Not (Acct_Code = 53 and ACTType in (1,2,3,4,5,6,7))
)
AS PriorAccts,
(SELECT
SUM(act_bal)
FROM table1
where date = '10/31/13'
and Pro_Group in ('BB','FF')
and prop_cat not in ('retail', 'personal')
and Not (Acct_Code = 53 and ACTType in (1,2,3,4,5,6,7))
)
AS PriorBal
from table1
where date = '01/31/14'
and Pro_Group in ('BB','FF')
and prop_cat not in ('retail', 'personal')
and Not (Acct_Code = 53 and ACTType in (1,2,3,4,5,6,7))
group by prop_code, prop_cat
order by prop_cat
You can use a CASE with aggregates for this (at least in SQL Server, not sure about MySQL):
...
COUNT(CASE WHEN date='1/31/14' THEN act_num ELSE NULL END) as 'Accts'
,SUM(CASE WHEN date='1/31/14' THEN act_bal ELSE NULL END) as 'AcctBal'
,COUNT(CASE WHEN date='10/31/13' THEN act_num ELSE NULL END) as 'PriorAccts'
,SUM(CASE WHEN date='10/31/13' THEN act_bal ELSE NULL END) as 'PriorAcctBal'
....
WHERE Date IN ('1/31/14', '10/31/13')
I have two tables that I want to join and split with a case function depending on the values in one of the columns. (I know, sounds weird so let me explain)
It's a process where I run separate batches. Every batch has several samples that are measured in instances of voltage readings in several locations. My two tables looks like this:
Sample Readings
id id
BatchesID SampleID
... voltage
... location
When a batch is run, it takes one sample at a time and for every location (25 locations) it takes about 20 readings of the voltage before moving on to the next one.
I want to look at one batch at a time, and for every Sample.id, I want to gather the AVG(voltage) for all the locations. My table for Readings turns out like:
SampleID location voltage
1 1 5.23
1 1 4.53
... ... ...
1 25 7.89
2 1 4.96
2 1 5.04
... ... ...
2 25 6.09
...
But I want it to look like:
SampleID avg_v_for_1 avg_v_for_2 ... avg_v_for_25
1 4.73 5.24 ... 6.35
2 3.87 4.76 ... 9.32
... ... ... ... ...
200 6.73 3.87 ... 8.23
Basically, what I want to do is for every separate sample, I want to take the average voltage for all the measurements in every location and put in on a single row. What my current syntax looks like is this:
SELECT Readings.SampleID, Sample.BatchesID
(case when location = '1' then AVG(voltage) else 0 end) avg_v_for_1,
(case when location = '2' then AVG(voltage) else 0 end) avg_v_for_2,
...
(case when location = '25' then AVG(voltage) else 0 end) avg_v_for_25
FROM DB.Readings
INNER JOIN Sample
ON Readings.SampleID = Sample.id
WHERE Sample.BatchesID = 'specific_batch_id'
GROUP BY Readings.location, Sample.id;
The problem is that this generates the following table:
SampleID avg_v_for_1 avg_v_for_2 ... avg_v_for_25
1 4.73 0 ... 0
1 0 4.76 ... 0
1 0 0 ... 6.73
2 3.87 0 ... 0
2 0 4.83 ... 0
...
How can I get MySQL to gather ALL the average values for EVERY location on a SINGLE row? I have tried removing the group by location and only group by sampleID but then I only get the values for the first location and everything else becomes 0.
Any help is appreciated, thank you!
I add another answer with explanation how the the query with AVG(case ..when ... then..end) works, and why the version with case ... when ... then AVG(..) end doesn't give expected results.
The first remark: the ANSI SQL standard for group by queries is the following:
SELECT column1, column2, ... column_n, aggregate_function (expression)
FROM tables
WHERE predicates
GROUP BY column1, column2, ... column_n;
where aggregated_function can be a function such a: SUM, MAX, MIN, COUNT, AVG
There are several rules (restrictions) for the GROUP BY CLASUE, see this link for details: http://etutorials.org/SQL/Mastering+Oracle+SQL/Chapter+4.+Group+Operations/4.2+The+GROUP+BY+Clause/
one of them says that:
GROUP BY clause must include all nonaggregate expressions
It means, that all columns in SELECT clause must be listed in the GROUP BY clause,
for example this query:
SELECT col1, col2, AVG( expression )
FROM table
GROUP BY col2
is wrong, because col1 is not listed in the GROUP BY clause, and this query won't work on all databases (Oracle, Postgresql, MS-SQL etc.) - except MySql (why - I'll tell about it later).
The expression within the aggregated function can refer to all columns of the table, regardless of the column is listed in the GROUP BY clause or not.
Because of the above the query:
SELECT Readings.SampleID,
(case when location = '1' then AVG(voltage) else 0 end) avg_v_for_1
....
GROUP BY sampleId
simply won't work on all databases that are compliant with ANSI SQL, this query will give a syntax error because location is out of AVG function, but is not listed in the GROUP BY clause.
The question - why this query works on MySql ?
Because MySql implemented it's own extension to the GROUP BY query, see this link --> http://dev.mysql.com/doc/refman/5.6/en/group-by-extensions.html
In MySql the select list can refer to nonaggregated columns not listed in the GROUP BY clause. Becaue of this extension our query is syntactically correct and runs on MySql, but gives unexpected (unwanted) results, since an order of expression's evaluation is different:
1. it first runs an aggregated (group by) query and evaluates AVG( price ),
2. then evaluates CASE WHEN ... THEN, but for resultset returned by the aggregated query from point 1
The query with the clause AVG( case when ... then ):
1. first calucates the expression CASE-WHEN-THEN for all table rows
2. then runs an aggregated query for resultset returned by #1 and calculates the AVG.
Try:
SELECT Readings.SampleID, Sample.BatchesID
AVG(case when location = '1' then voltage else null end) avg_v_for_1,
AVG(case when location = '2' then voltage else null end) avg_v_for_2,
...
AVG(case when location = '25' then voltage else null end) avg_v_for_25
FROM DB.Readings
........
GROUP BY sample_id
--- EDIT --> use ifnull function to change nulls into 0
SELECT Readings.SampleID, Sample.BatchesID
ifnull( AVG(case when location = '1' then voltage else null end), 0 ) avg_v_for_1,
ifnull( AVG(case when location = '2' then voltage else null end), 0 ) avg_v_for_2,
...
ifnull( AVG(case when location = '25' then voltage else null end), 0 ) avg_v_for_25
FROM DB.Readings
........
GROUP BY sample_id