Resolve inconsistency between VARCHAR and STRING

[ybyzek]

Porting confluentinc/ksqldb-recipes#146 here

confluentinc/ksqldb-recipes#131 (comment)

Looking for clarification on differentiation of VARCHAR vs STRING and when to use which. I usually see VARCHAR in the context below, but STRING also works:

CREATE STREAM pages (
   page STRING, ....

We have recipes that reference both...

ksqlDB uses STRING as synonym to VARCHAR -- so semantically there is no difference.

VARCHAR is the standard SQL type, even if it actually needs a "max size" parameter that ksqlDB does not implement. -- STRING is no standard SQL type (seems to be syntactic sugar -- but sure why ksqlDB added it). To technically neither VARCHAR nor STRING is standard SQL...

To avoid confusing users, it might be good to just pick either one and use it exclusively in all tutorials.

Vote from @mjsax is to use VARCHAR