Combining two independent inner joins into one on certain conditions - sql

Question

I have the below two queries that are shown below, actually both of the queries use an inner join internally. Now I want to combine these two queries into one, but the condition that where the value of column invo_id = 2 and the column invo_id is in table ioa_invoice_line
So the relationship among three tables
ioa_invoice_line
ioa_invoice_line_notes
IOA_INV_LINE_NOTE_MAP
These are the queries
select
e.id
, e.invo_id
, b.id
, b.inli_id
from
ioa_invoice_line e
inner join
ioa_invoice_line_notes b on e.id = b.inli_id;
select
e.id
, b.id
, b.ATTACHMENT_BLOB_ID
, b.INV_LINE_NOTE_ID
from
ioa_invoice_line_notes e
inner join
IOA_INV_LINE_NOTE_MAP b on e.id = b.INV_LINE_NOTE_ID;
ioa_invoice_line enter image description here

Answer 1

This is the way I assumed you'd want to do the joins. Since you're looking for two conditions to be true:
1) That ioa_invoice_line.invo_id = 2
2) That ioa_invoice_line.invo_id exists
Since you'll be checking to see that invo_id is equal to 2 you can be pretty sure that it exists if it finds a value of 2.
SELECT L.id, L.invo_id, LN.id, LNM.id, LNM.attachment_blob_id, LNM.inv_line_note_id
FROM ioa_invoice_line_notes LN
INNER JOIN ioa_invoice_line L ON LN.inli_id = L.id
INNER JOIN ioa_inv_line_note_map LNM ON LN.id = LNM.inv_line_note_id
WHERE L.invo_id = 2;
It just looked like you were looking for Inv Line ID, Inv Line Invoice ID, Line Notes ID, Line Notes Map ID and the other IDs in the Notes Map table.

Answer 2

The query integrates the condition on the invo_id into the join. As it is an inner join, the existence of invo_id in the selected records comes for free:
select line.id id_line
, line.invo_id
, notes.id id_notes
, notes.inli_id
, map.id id_map
, map.attachment_blob_id
, map.inv_line_note_id
from ioa_invoice_line line
INNER JOIN ioa_invoice_line_notes notes on (
line.id = notes.inli_id
AND line.invo_id = 2
)
INNER JOIN ioa_inv_line_note_map map on map.id = notes.inv_line_note_id
;