[whakim]

My experience is that almost any startup needs to write some complex SQL and has to deal with slow query performance, so at least one or two engineers tend to be good at SQL/databases/query plans/indexing/etc. They may not be as knowledgeable or useful as a full dedicated Database Engineer/DBA, but at least you have indices/someone who enjoys writing SQL/someone who thinks about query performance.

[samus]

Or they don't and then conclude that SQL and relational DBMSs are crap and that they have to switch to NoSQL to save the day (/s but only slightly)