We have a table test in which we have status_cd as one of the column. Status Code can have three value - Prelim, Approved and confirmed.
I have to write a query in such a way that it should fetch the record for confirmed status cd. If confirmed status cd is not present, then fetch for Approved, if approved is not present, fetch for prelim, if prelim is also not present, fetch for null
id rule_id status_cd
1 1 prelim
2 1 null
3 1 approved
in above example, the query should return approved for rule_id=1
Try this way:
SELECT T1.*
FROM test T1 JOIN
(SELECT *,CASE status_cd WHEN 'confirmed' THEN 1
WHEN 'approved' THEN 2
WHEN 'prelim' THEN 3
ELSE 4 END AS Rank
FROM test) T2 ON T1.id=T2.id AND T1.Rule_id =T2.Rule_id
ORDER BY T2.Rank
LIMIT 1
Result:
ID RULE_ID STATUS_CD
3 1 approved
Sample result in SQL Fiddle.
Use the values '3 Confirmed','2 Approved', '1 Prelim' and '0 Null' or just use a default value of zero in a numerical field and set the value to 1, 2, 3 as the rule progresses (much faster execution, but avoid the null either way by using a default value of '0 Null' in the field if you keep a string implementation).
Then fetch the records with this query:
SELECT status_cd FROM YourTableName WHERE rule_id=1 ORDER BY status_cd DESC;
The first row of the query will always contain the answer you want. Additionally, the other rows will be there to confirm that all the other steps were present, etc. if you want to look at those rows too. If you know you only need the one row, then use
SELECT TOP 1 status_cd FROM ... (the rest is the same)
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 want count the length of a comma separated column
I have use these
(LENGTH(Col2) - LENGTH(REPLACE(Col2,",","")) + 1)
in my select query.
Demo:
id | mycolumn
1 2,5,8,60
2 4,5,1
3 5,Null,Null
query result for first two row is coming correctly.for 1 = 4 ,2 = 3 but for 3rd row it is calculating null value also.
Here is what I believe the actual state of your data is:
id | mycolumn
1 2,5,8,60
2 4,5,1
3 NULL
In other words, the entire value for mycolumn in your third record is NULL, likely from doing an operation involving a NULL value. If you actually had the text NULL your current query should still work.
The way to get around this would be to use COALESCE(val, "") when handling the NULL values in your strings.
Crude way of doing it is to replace the occurances of ',Null' with nothing first:-
SELECT a.id, (LENGTH(REPLACE(mycolumn, ',Null', '')) - LENGTH(REPLACE(REPLACE(mycolumn, ',Null', ''),",","")) + 1)
FROM some_table a
If the values refer to the id of rows in another table then you can join against that table using FIND_IN_SET and then count the matches (assuming that the string 'Null' is not an id on that other table)
SELECT a.id, COUNT(b.id)
FROM some_table a
INNER JOIN id_list_table b
ON FIND_IN_SET(b.id, a.mycolumn)
GROUP BY a.id
I try to get the max value of a mysql select, but want to have it null/empty/0 if there is one row containing no timestamp.
Table stats (simplyfied):
ID CLIENT ORDER_DATE CANCEL_DATE
1 5 1213567200
2 5 1213567200
3 6 1210629600 1281736799
4 6 1210629600 1281736799
5 7 1201042800 1248386399
6 7 1201042800
7 8 1205449200 1271282399
I'm now looking to get the lowest order date (no problem, as it is never empty), and
the maximum cancel date. If the client has already cancelled his subscription, the cancel date is filled, but if he is still active, there is no cancel date at all.
Query:
SELECT ID, min(ORDER_DATE) AS OD, max(CANCEL_DATE) AS CD FROM stats GROUP BY CLIENT
Returns:
ID OD CD
5 1213567200 // fine
6 1210629600 1281736799 // fine
7 1201042800 1248386399 // Should be empty
8 1205449200 1271282399 // fine
I can't figure it out how to return empty/0/NULL if there is one (or more) empty colums for a client. Also tried with NULL fields.
Thanks for any hint.
I don't know how fast it will be but I guess it can be solved like this:
SELECT ID, min(ORDER_DATE) AS OD,
IF(COUNT(*)=COUNT(CANCEL_DATE),max(CANCEL_DATE),NULL) AS CD
FROM stats GROUP BY CLIENT
I couldn't test it but the idea behind this solution is that count(cancel_date) should count all not null value entries and if it's equal to count(*) that means that there are no null values and it will return max(cancel_date), otherwise null.
You could use a query like this:
SELECT
client,
min(ORDER_DATE) AS OD,
case when MAX(CANCEL_DATE IS NULL)=0 THEN max(CANCEL_DATE) END AS CD
FROM
stats
GROUP BY
CLIENT
Please see fiddle here.
CANCEL_DATE IS NULL will be evaluated either to 0, when CANCEL_DATE is not null, or to 1 when it is null
MAX(CANCEL_DATE IS NULL) will be evaluated to 0 if there are no cancel_date with null values, otherwise its value will be 1.
when MAX(CANCEL_DATE IS NULL)=0 it means that there are no rows where CANCEL_DATE is null, and we need to return MAX(cancel_date) in that case, otherwise we need to return NULL.
I need help with a SQL query.
I have a table with a 'state' column. 0 means closed and 1 means opened.
Different users want to be notified after there have been x consecutive 1 events.
With an SQL query, how can I tell if the last x rows of 'state' = 1?
If, for example, you want to check if the last 5 consecutive rows have a state equals to 1, then here's you could probably do it :
SELECT IF(SUM(x.state) = 5, 1, 0) AS is_consecutive
FROM (
SELECT state
FROM table
WHERE Processor = 3
ORDER BY Status_datetime DESC
LIMIT 5
) as x
If is_consecutive = 1, then, yes, there is 5 last consecutive rows with state = 1.
Edit : As suggested in the comments, you'll have to use ORDER BY in your query, to get the last nth rows.
And for more accuracy, since you have a timestamp column, you should use Status_datetime to order the rows.
You should be able to use something like this (replace the number in the HAVING with the value of x you want to check for):
SELECT Processor, OpenCount FROM
(
SELECT TOP 10 Processor, DateTime, Sum(Status) AS OpenCount
FROM YourTable
WHERE Processor = 3
ORDER BY DateTime DESC
) HAVING OpenCount >= 10
I would like to manipulate the result I get from a query.
I have a set of 2.5m rows and there are 10 different ID's for a status. These statusses are not mapped in another table but I would like to manipulate the result I get in SQLyog.
What I would like to do is:
Count(Id) | Status
------------------
500.000 | 1
750.000 | 2
convert into a result
Count(Id) | Status
-------------------
500.000 | Initial order
750.000 | Cancelled
Can this be done in the query? Note that I'm not using PHP or a browser to display the results.
select
count(*) as TotalRecs,
case status
when 1 then "Initial Order"
when 2 then "Cancelled "
when 3 then "whatever "
else "all others "
end case as WordStatus
from
YourTable
group by
2
You can either inline it in a case statement
select COUNT(id),
case status
when 1 then 'initial order'
when 2 then 'cancelled'
# without an else, the rest go to NULL
end status
from tbl
group by status # yes, just on status
Or I would strongly encourage you to create a reference table for this
Tbl Status contains 2 columns ID and Description
select COUNT(tbl.id), status.description
from tbl
LEFT join status on status.id = tbl.status
group by status.description