When should I use Sql Azure and when should I use table Storage?

Question

When should i use Sql Azure and when should I use table Storage? I was thinking , use table storage for transaction processing scenarios e.g. debit credit accounts kind of

Answer 1

Igor and Mark gave great answers. Let me add just a bit more...

With SQL Database (formerly named SQL Azure), you can now have databases up to 500GB. To go beyond that, you'd need to partition your data. Note: Originally I suggested shards with SQL Federations, but this feature has since been retired.

ATS does offer transactions at the partition level (entity group transactions). See this MSDN article for more information. This is not as robust as SQL Azure transactions, but it does allow for batch operations in a single transaction.

EDIT It's been over a year since this question was asked (and answered). One comparison point was on pricing. While SQL Azure is still more expensive than ATS, the cost of SQL Azure has dropped significantly in the past year. Databases now have tiered pricing, starting at $4.99 for 100MB, increasing to $225 for 150GB (a big drop from the $9.99 / GB pricing from last year. Full pricing details are here.

EDIT Aug 2014 Another year later, another update. While web/business tiers continue to exist, they are being sunsetted (and SQL Federations is no longer available). The new Basic, Standard, and Premium tiers are now available (see here for details).