COALESCE vs OR condition for JOIN (SQL)

Question

I have Event table

TABLE Event(
EventId [int] IDENTITY(1,1) NOT NULL,
EventSource1Id [int] NULL,
EventSource2Id [int] NULL
)

that contains info about events from different sources where one of the event sources can be null

TABLE EventSource1(
Id [int] IDENTITY(1,1) NOT NULL,
Name [nvarchar](50) NULL,
VenueId [int] NOT NULL
)

and

TABLE EventSource2(
Id [int] IDENTITY(1,1) NOT NULL,
Name [nvarchar](50) NULL,
VenueId [int] NOT NULL
)

TABLE Venue(
Id [int] IDENTITY(1,1) NOT NULL,
TimeZone [nvarchar](100) NOT NULL
)

I'd like to create view, but I'm not sure what is the best way to use: coalesce vs OR condition for JOIN

First option:

SELECT 
ev.[Id] AS 'Id',
ven.[Id] AS 'VenueId'
FROM Event ev
LEFT JOIN EventSource1 source1 ON source1.[Id] = ev.EventSource1Id
LEFT JOIN EventSource2 source1 ON source2.[Id] = ev.EventSource2Id
LEFT JOIN Venue AS ven ON ven.[Id] = source1.[VenueId] OR v.[Id] = source2.[VenueId]

Second option:

SELECT 
ev.[Id] AS 'Id',
ven.[Id] AS 'VenueId'
FROM Event ev
LEFT JOIN EventSource1 source1 ON source1.[Id] = ev.EventSource1Id
LEFT JOIN EventSource2 source1 ON source2.[Id] = ev.EventSource2Id
LEFT JOIN Venue AS ven ON ven.[Id] = COALESCE(source1.[Id], source2.[Id])

Could you help me please?

Answer 1

The COALESCE will typically yield a better query plan. You should test with your data.