|| represents string concatenation. Unfortunately, string concatenation is not completely portable across all sql dialects:
- ansi sql:
||(infix operator) - mysql:
concat( vararg function ). caution:||means ‘logical or’ (It’s configurable, however; thanks to @hvd for pointing that out) - oracle:
||(infix operator),concat( caution: function of arity 2 only ! ) - postgres:
||(infix operator) - sql server:
+(infix operator),concat( vararg function ) - sqlite:
||(infix operator)
hopefully the confusion is complete …