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Eniola Tijani
3,440 Pointssql query
Suppose there is a database with two tables namely Loans and Billpayment.
For the Loans table I have the following columns: loanId, clientId(primary key), DisbursementDate, applicationDate, approvalDate, loanNumber, loanAmount, interestRate
For the Billpayment table I have the following columns: billId(primary), customerId(foreign), billAmount, payment_status[success/fail] billDate
note: billdate in timestamp
bill is considered paid if payement status is 'success'
1 )How can I get the clients that had a bill payment in March 2018, 2) show the number of those clients that made at least one bill payment in the remaining months of 2018, 3) show whether or not the bill payment clients have a loan within 2018 or not
1 Answer
Brendan Whiting
Front End Web Development Techdegree Graduate 84,736 PointsYou'll want to use a join. Something like this:
SELECT * FROM Loans
INNER JOIN Billpayment
ON Loans. clientId = Billpayment.customerId
/* some WHERE conditions... /*
You also may need to first create some subqueries or common table expressions to narrow down the results of one table before you join it. So you could have a subquery for "clients that had a bill payment in March 2018" and "clients that made at least one bill payment in the remaining months of 2018" and then join from that subquery.
Eniola Tijani
3,440 PointsEniola Tijani
3,440 Pointsthank you brendan ..but the approach i took is to create a temp table for customers that had a billpayement in march and futher more i used the IN clause to get the number of those clients that made at least one bill payment in the remaining months of 2018..but trying to show whether or not the bill payment clients have a loan within 2018 or not is where i keep getting stuck.. please can u kindly explain further with the approach u have taken
Brendan Whiting
Front End Web Development Techdegree Graduate 84,736 PointsBrendan Whiting
Front End Web Development Techdegree Graduate 84,736 PointsAre you using a
joinanywhere?It's hard for me to figure out the details without access to the data. The SQL Track here at Treehouse is very good. I also recommend this course on Codecademy: Analyzing Business Metrics.