Fruity beer is also common in Belgium. It’s not mixed with juice but is already flavored in the bottle as you buy it. And yes, it’s delicious. Kriek for instance is a pretty famous cherry flavored beer.
Also non-alcaholic beer mixed with juice is a pretty decent drink after sports. The slight bitterness and the bubbles makes it really refreshing on hot days.
It’s not about a flavoured beer - there’s plenty of em. This is about a concentrated form of juice you usually dilute in water. You put it into beer, it turns reddish-pink and a lot of people preffer to drink it that way
Pubs in the UK used to (or still do?) have blackcurrant and lime cordial for this.
“Lager and Lime”, “Lager and Blackcurrant” and “Cider and Blackcurrant” were pretty common 20-30 years ago. A shot of cordial (concentrated juice), then filled up with lager beer.
There was also orange cordial behind the bar, but nobody ever drank “Lager and orange”. I believe it was some form of crime.
There’s also snakebite, which IIRC is Lager, Cider, and a shot of blackcurrant cordial. A great drink to get you off your tits when you’re young.