How can I set a column value to one of 3 values based on a specific condition?
For example, I have a table called Customer with an attribute called customer_level, where this customer can have one of 3 possible levels.
Each customer will have an attribute called customer_spent, which will show how much the customer has spent.
I have a condition where if a Customer spends >= 100, they are given the S rank. If a Customer spends >= 50 but < 100, they are given the A rank. If a Customer spends >= 0 but < 50, they are given the B rank.
So, how would I make it so when one of the conditions is matched, the customer_level will be set to either S, A or B?
I am currently trying to write this in the form of an UPDATE statement for the Customer table but am unsure of how to structure the statement.
Thanks!
In Oracle there is a CASE/WHEN expression:
SELECT
CASE WHEN spent >= 100
THEN 'S'
WHEN spent >= 50 AND spent < 100
THEN 'A'
WHEN spent > 0 AND spent < 50
THEN 'B'
ELSE 'NONE'
END as rank from table;
Related
I want to get a count of cells in Column A that meet a criteria (average of 10 minutes or more) in Column B using SQL. Apologies as I'm definitely not an SQL expert. Column B has wait times by second and I need to change it to minute, so basically my equation would be Column_B/60, but then also I want to only count the cells in Column A that have an average of 10 minutes or more in Column B. My current formula is below, I know it's off but to give an idea:
COUNT(CASE Column_A
WHERE Column_B/60 >= 10)
END
You can try
SELECT COUNT(*) FROM table_name WHERE Column_B/60 >= 10;
It can be achieved using the two step process below:
1) HH:MM:SS
To display Column_B in an HH:MM:SS format, set the Field Type to:
Number > Duration (Sec.)
If required, change the aggregation as required, such as to AVG.
2) CASE Statement
One way that it can be achieved is by displaying the Column_B value in seconds (60 seconds * 10 minutes):
COUNT(CASE
WHEN Column_B >= 600 THEN Column_A
ELSE NULL END)
Google Data Studio Report and a GIF to elaborate:
I have a "daily changes" table that records when a customer "upgrades" or "downgrades" their membership level. In the table, let's say field 1 is customer ID, field 2 is membership type and field 3 is the date of change. Customers 123 and ABC each have two rows in the table. Values in field 1 (ID) are the same, but values in field 2 (TYPE) and 3 (DATE) are different. I'd like to write a SQL query to tell me how many customers "upgraded" from membership type 1 to membership type 2 how many customers "downgraded" from membership type 2 to membership type 1 in any given time frame.
The table also shows other types of changes. To identify the records with changes in the membership type field, I've created the following code:
SELECT *
FROM member_detail_daily_changes_new
WHERE customer IN (
SELECT customer
FROM member_detail_daily_changes_new
GROUP BY customer
HAVING COUNT(distinct member_type_cd) > 1)
I'd like to see an end report which tells me:
For Fiscal 2018,
X,XXX customers moved from Member Type 1 to Member Type 2 and
X,XXX customers moved from Member Type 2 to Member type 1
Sounds like a good time to use a LEAD() analytical function to look ahead for a given customer's member_Type; compare it to current record and then evaluate if thats an upgrade/downgrade then sum results.
DEMO
CTE AS (SELECT case when lead(Member_Type_Code) over (partition by Customer order by date asc) > member_Type_Code then 1 else 0 end as Upgrade
, case when lead(Member_Type_Code) over (partition by Customer order by date asc) < member_Type_Code then 1 else 0 end as DownGrade
FROM member_detail_daily_changes_new
WHERE Date between '20190101' and '20190201')
SELECT sum(Upgrade) upgrades, sum(downgrade) downgrades
FROM CTE
Giving us: using my sample data
+----+----------+------------+
| | upgrades | downgrades |
+----+----------+------------+
| 1 | 3 | 2 |
+----+----------+------------+
I'm not sure if SQL express on rex tester just doesn't support the sum() on the analytic itself which is why I had to add the CTE or if that's a rule in non-SQL express versions too.
Some other notes:
I let the system implicitly cast the dates in the where clause
I assume the member_Type_Code itself tells me if it's an upgrade or downgrade which long term probably isn't right. Say we add membership type 3 and it goes between 1 and 2... now what... So maybe we need a decimal number outside of the Member_Type_Code so we can handle future memberships and if it's an upgrade/downgrade or a lateral...
I assumed all upgrades/downgrades are counted and a user can be counted multiple times if membership changed that often in time period desired.
I assume an upgrade/downgrade can't occur on the same date/time. Otherwise the sorting for lead may not work right. (but if it's a timestamp field we shouldn't have an issue)
So how does this work?
We use a Common table expression (CTE) to generate the desired evaluations of downgrade/upgrade per customer. This could be done in a derived table as well in-line but I find CTE's easier to read; and then we sum it up.
Lead(Member_Type_Code) over (partition by customer order by date asc) does the following
It organizes the data by customer and then sorts it by date in ascending order.
So we end up getting all the same customers records in subsequent rows ordered by date. Lead(field) then starts on record 1 and Looks ahead to record 2 for the same customer and returns the Member_Type_Code of record 2 on record 1. We then can compare those type codes and determine if an upgrade or downgrade occurred. We then are able to sum the results of the comparison and provide the desired totals.
And now we have a long winded explanation for a very small query :P
You want to use lag() for this, but you need to be careful about the date filtering. So, I think you want:
SELECT prev_membership_type, membership_type,
COUNT(*) as num_changes,
COUNT(DISTINCT member) as num_members
FROM (SELECT mddc.*,
LAG(mddc.membership_type) OVER (PARTITION BY mddc.customer_id ORDER BY mddc.date) as prev_membership_type
FROM member_detail_daily_changes_new mddc
) mddc
WHERE prev_membership_type <> membership_type AND
date >= '2018-01-01' AND
date < '2019-01-01'
GROUP BY membership_type, prev_membership_type;
Notes:
The filtering on date needs to occur after the calculation of lag().
This takes into account that members may have a certain type in 2017 and then change to a new type in 2018.
The date filtering is compatible with indexes.
Two values are calculated. One is the overall number of changes. The other counts each member only once for each type of change.
With conditional aggregation after self joining the table:
select
2018 fiscal,
sum(case when m.member_type_cd > t.member_type_cd then 1 else 0 end) upgrades,
sum(case when m.member_type_cd < t.member_type_cd then 1 else 0 end) downgrades
from member_detail_daily_changes_new m inner join member_detail_daily_changes_new t
on
t.customer = m.customer
and
t.changedate = (
select max(changedate) from member_detail_daily_changes_new
where customer = m.customer and changedate < m.changedate
)
where year(m.changedate) = 2018
This will work even if there are more than 2 types of membership level.
The title is a bit confusing but I'll explain my problem here:
So i have a database table with millions of lines of spending data broken up into different time fields (period1 - period14). Now what i need to do is write a query that will return the records where the spending in one period is equal to the spending in a different period within the same record. So basically that means if i have a reecord where the spending in period1 is $100 and then the spending in period5 is also $100, it will add that record to a new table. I tried something like the code below but since I'm very new to access it is rather complex/inefficient and also doesn't do what i need it to.
INSERT INTO Contracts
SELECT *
FROM SPENDDETAIL
WHERE (SPENDDETAIL.Period1 = SPENDDETAIL.Period2 OR SPENDDETAIL.Period3 [...] OR SPENDDETAIL.Period14)
AND (SPENDDETAIL.Period1 <> 0 OR SPENDDETAIL.Period2 <> 0 [...] OR SPENDDETAIL.Period14 <> 0);
Any help much appreciated, thanks!
Oh also i know this code snippet would only return the records where the period1 spend equals the spend from any of the other periods it was just a beginning attempt at making the query do what i need it to.
Something along these lines might get you started:
SELECT Id, Value, COUNT(*) FROM
(SELECT Id AS Id, 1 AS Period, Period1 AS Value FROM SPENDDETAIL
UNION ALL
SELECT Id AS Id, 2 AS Period, Period2 AS Value FROM SPENDDETAIL
UNION ALL
SELECT Id AS Id 3 AS Period, Period3 AS Value FROM SPENDDETAIL
etc...) x
GROUP BY Id, Value
HAVING COUNT(*) > 1
Where Id is some unique identifier for each row of the data (assuming there is such a thing).
This will give you a list of Ids and matching values.
I work with a huge dataset of hospital activity records. Each record represents something done on behalf of a patient. My focus is on patients that have experienced 'outpatient' activity, such as attended an appointment or clinic.
In the data, we get records that are duplicates in that; a patient is shown to have attended their first out patient appointment more than once in a six month period. This is an error on the part of the hospital who send their data. We have to identify these records to send back as challenges.
I have the following SQL statement which is finding records where the 'Patient Code' appears more than once.
SELECT * FROM dbo.Z_ForQueries a
JOIN (SELECT PatientCode
FROM dbo.Z_ForQueries
GROUP BY PatientCode
HAVING COUNT (*) > 1 ) b
ON a.PatientCode = b.PatientCode
WHERE [Multiple OPFA in month] = 'y'
I cannot for the life of me figure out how to syntax the next bit; For each set of duplicated patient codes, I only want to see the records where one of the records has a 'Month' of 7 (that's the just the current month I'm working on). If non of the groups of duplicated records have '7' in the month, then I don't need to see them.
For example, patient code L000066715 has 4 records, I can see that each record represents the same initial outpatient appointment in the same hospital speciality. Obviously you can only 'first attend' once. Each record has a month number; 3,4,6 & 7. Because this patient code has one of their duplicate records in month 7, I need it to be returned in the results along with the other 3 records.
Other patient codes exist in duplicate but none of their records are from month 7, so they don't need to be returned.
I hope I've set the scene properly for some help! Thanks.
Something like this should work:
SELECT *
FROM dbo.Z_ForQueries a
JOIN (
SELECT PatientCode,
MAX(CASE WHEN MONTH(dateColumn) = 7 THEN 1 ELSE 0 END) As InMonth
FROM dbo.Z_ForQueries
GROUP BY PatientCode
HAVING COUNT (*) > 1
) b ON a.PatientCode = b.PatientCode
And InMonth = 1
WHERE [Multiple OPFA in month] = 'y'
Explanation:
The CASE expression returns 1 for rows where Month=7, and 0 in all other cases. The MAX(..) around this CASE expressions thus returns 1 if any rows in the GROUP had a Month=7 and a 0 only if none of them did.
I would like to thank in advance for any help.
My problem relates to two tables in MySQL (Now switching to postgresql). The tables are related to a ticketing database.
a) booking. It has four columns ccode,date,time,amount
b) account It has three columns ccode,date,amount
The booking table has ticket bookings and account table has advances and payments received.
I have to prepare a statement of account based on ccode (customer code).
The statement shows columns as below
*Ccode Type Date time amount balance*
- the report in sorted on ccode and then on date (account table row appears first)
- Type column displays B or A depending on record type
- Time column is present only in booking table
- Report has a running balance for each row
- At the end for a customercode, the totals of amount and balance is displayed
I have had success, so far in creating a join as below. (and after dicussion below, have been able to generate TYPE column using IF)
SELECT booking.cname, booking.bdate, booking.btime, booking.rate, booking.ID,
IF(booking.btime IS NOT NULL, "B", "A") AS type, account.cname, account.date,
account.amount, account.ID
FROM booking
LEFT JOIN account ON booking.bdate = account.date AND booking.cname=account.cname AND
booking.rate = account.amount
UNION
SELECT booking.cname, booking.bdate, booking.btime, booking.rate, booking.ID,
IF(booking.btime IS NOT NULL, "B", "A") AS type, account.cname, account.date,
account.amount, account.ID
FROM booking
RIGHT JOIN account ON booking.bdate = account.date AND booking.cname=account.cname AND
booking.rate = account.amount
It displays all the records. A report can be generated using this table.
But is there a way to display the formatted report just by SQL.
I can change the order of columns and even add or remove existing ones as long as Record type is known and a running balance is displayed against each record.
A SAMPLE REPORT ---- REPORT A
CODE DATE TYPE AMOUNT BALANCE TIME
A1 02/19/2011 A 50 50
A1 02/20/2011 B 35 15 1230
A1 02/21/2011 A 40 55
A1 02/21/2011 B 20 35 1830
optional > TOTAL Account = 90 Booking = 55 Balance = 35
A SAMPLE REPORT ---- REPORT B
CODE AMOUNT BOOKED AMOUNT PAID BALANCE
A1 50 50 0
A1 35 15 20
A1 40 55 -15
A1 20 35 -15
this is a weekly statement version of REPORT A.
the reason is i can add where and between to get only records in a given week.
and since it is a weekly report, running balance is just omitted.
It is report grouped for all entries with customercode A1 present
in booking and account tables.
thanx
Since your data is not normalized for this, you pay the price in query complexity, as shown below:
SELECT ccode, date, time, type, amount,
(SELECT SUM(amount) AS balance
FROM numbered AS n
WHERE numbered.rownum <= n.rownum AND numbered.ccode = n.ccode) AS balance
FROM (SELECT sorted.*, #rownum := #rownum + 1 AS rownum
FROM (SELECT *
FROM (SELECT ccode, date, time, 'B' AS type, amount
FROM booking
UNION
SELECT ccode, date, "0000" AS time, 'A' AS type, -amount
FROM account) AS unsorted
ORDER BY ccode, date, time, type) AS sorted) AS numbered
The idea here is that you first need to get your booking (debits) and account (credits) lined up as in the "unsorted" statement above. Then, you need to sort them by date and time as in the "sorted" statement. Next, add row numbers to the results as in the "numbered" statement. Finally, select all that data along with a sum of amounts with row number less than or equal to the current row number that matches your ccode.
In the future, please consider using a transaction table of some sort which holds all account balance changes in a single table.
I have found the answer.
It is to use cummulative sql statement to find a running balance