Postgres GROUP BY, SUBSTRING and SUM Query Issue - sql

Question

I am trying to write a GROUP BY query but I am struggling to achieve the desired result. I am including
A JSON object that represent the DB table with some data.
SELECT * FROM tb_transaction
"tb_transaction": [
{
"id": "121",
"profile_id": "57",
"event_id": "45",
"activity_id": "67",
"payment_type": "EFT",
"transaction_type": "activity_registration",
"gl_code": "1234-56-102-020",
"description": "Golf",
"amount": "1500",
"paid": "f",
"invoice_number": "0006"
},
{
"id": "117",
"profile_id": "57",
"event_id": "45",
"activity_id": "65",
"payment_type": "EFT",
"transaction_type": "activity_registration",
"gl_code": "1234-56-102-056",
"description": "Cuppa",
"amount": "100",
"paid": "f",
"invoice_number": "0006"
},
{
"id": "120",
"profile_id": "57",
"event_id": "45",
"activity_id": "70",
"payment_type": "EFT",
"transaction_type": "activity_registration",
"gl_code": "1234-13-102-064",
"description": "Nutrition & Lifestyle",
"amount": "510",
"paid": "f",
"invoice_number": "0006"
},
{
"id": "125",
"profile_id": "207",
"event_id": "45",
"activity_id": "65",
"payment_type": "Cash",
"transaction_type": "activity_registration",
"gl_code": "1234-56-102-056",
"description": "Cuppa",
"amount": "100",
"paid": "f",
"invoice_number": "0007"
},
{
"id": "126",
"profile_id": "207",
"event_id": "45",
"activity_id": "65",
"payment_type": "Cash",
"transaction_type": "merchandise",
"gl_code": "3400-56-102-056",
"description": "Cap",
"amount": "20",
"paid": "f",
"invoice_number": "0007"
},
{
"id": "128",
"profile_id": "193",
"event_id": "45",
"activity_id": "70",
"payment_type": "SnapScan",
"transaction_type": "activity_registration",
"gl_code": "1234-13-102-064",
"description": "Nutrition & Lifestyle",
"amount": "510",
"paid": "f",
"invoice_number": "0008"
},
{
"id": "131",
"profile_id": "193",
"event_id": "45",
"activity_id": "65",
"payment_type": "SnapScan",
"transaction_type": "merchandise",
"gl_code": "3400-56-102-056",
"description": "Water Bottle",
"amount": "10",
"paid": "f",
"invoice_number": "0008"
},
{
"id": "130",
"profile_id": "193",
"event_id": "45",
"activity_id": "65",
"payment_type": "SnapScan",
"transaction_type": "activity_registration",
"gl_code": "1234-56-102-056",
"description": "Cuppa",
"amount": "100",
"paid": "f",
"invoice_number": "0008"
}
]
My current query and its result.
SELECT gl_code, transaction_type, activity_id, payment_type, description, SUM(amount) AS amount
FROM tb_transaction
WHERE event_id = 45 AND paid = false
GROUP BY gl_code, transaction_type, activity_id, payment_type, description
ORDER BY gl_code;
"RECORDS": [
{
"gl_code": "1234-13-102-064",
"transaction_type": "activity_registration",
"activity_id": "70",
"payment_type": "EFT",
"description": "Nutrition & Lifestyle",
"amount": "510"
},
{
"gl_code": "1234-13-102-064",
"transaction_type": "activity_registration",
"activity_id": "70",
"payment_type": "SnapScan",
"description": "Nutrition & Lifestyle",
"amount": "510"
},
{
"gl_code": "1234-56-102-056",
"transaction_type": "activity_registration",
"activity_id": "65",
"payment_type": "Cash",
"description": "Cuppa",
"amount": "100"
},
{
"gl_code": "1234-56-102-056",
"transaction_type": "activity_registration",
"activity_id": "65",
"payment_type": "EFT",
"description": "Cuppa",
"amount": "100"
},
{
"gl_code": "1234-56-102-056",
"transaction_type": "activity_registration",
"activity_id": "65",
"payment_type": "SnapScan",
"description": "Cuppa",
"amount": "100"
},
{
"gl_code": "1234-56-102-020",
"transaction_type": "activity_registration",
"activity_id": "67",
"payment_type": "EFT",
"description": "Golf",
"amount": "1500"
},
{
"gl_code": "3400-56-102-056",
"transaction_type": "merchandise",
"activity_id": "65",
"payment_type": "Cash",
"description": "Cap",
"amount": "20"
},
{
"gl_code": "3400-56-102-056",
"transaction_type": "merchandise",
"activity_id": "65",
"payment_type": "SnapScan",
"description": "Water Bottle",
"amount": "10"
}
]
The desired result.
`"RECORDS": [
{
"gl_code": "1234-13-102-064",
"transaction_type": "activity_registration",
"activity_id": "70",
"payment_type": "EFT",
"description": "Nutrition & Lifestyle",
"amount": "510"
},
{
"gl_code": "1234-13-102-064",
"transaction_type": "activity_registration",
"activity_id": "70",
"payment_type": "SnapScan",
"description": "Nutrition & Lifestyle",
"amount": "510"
},
{
"gl_code": "1234-56-102-056",
"transaction_type": "activity_registration",
"activity_id": "65",
"payment_type": "Cash",
"description": "Cuppa",
"amount": "120"
},
{
"gl_code": "1234-56-102-056",
"transaction_type": "activity_registration",
"activity_id": "65",
"payment_type": "EFT",
"description": "Cuppa",
"amount": "100"
},
{
"gl_code": "1234-56-102-056",
"transaction_type": "activity_registration",
"activity_id": "65",
"payment_type": "SnapScan",
"description": "Cuppa",
"amount": "110"
},
{
"gl_code": "1234-56-102-020",
"transaction_type": "activity_registration",
"activity_id": "67",
"payment_type": "EFT",
"description": "Golf",
"amount": "1500"
}
]'
The difference is very subtle. But you will see that I basically want to sum the records who's "payment_type" and last 3 digits of the "gl_code" are the same. For example "payment_type": "Cash" and "gl_code": "1234-56-102-056",
Any help will be immensely appreciated.

Answer 1

If you want to group by payment_type and last 3 digits of gl_code (and apparently some other columns), you can do
SELECT substring(gl_code, length(gl_code) - 3),
transaction_type,
activity_id,
payment_type,
description,
SUM(amount) AS amount
FROM tb_transaction
WHERE event_id = 45 AND paid = false
GROUP BY substring(gl_code, length(gl_code) - 3),
transaction_type,
activity_id,
payment_type,
description
ORDER BY gl_code;
Note however that this will only select the last 3 digits, and not an (arbitrary) gl_code from all those that share the same last 3 digits.