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Writing Analytics SQL with Common Table Expressions
- groovy2shoes 12y agoSome RDBMSs support recursive CTEs, which come in handy sometimes. SQLite added support earlier this year, and I've written a handful of recursive CTEs to traverse DAGs in the database. I was blown away by how quickly SQLite can handle queries like that!
- batbomb 12y agoA few others: SQLite, Oracle, PostgreSQL, DB2, HSQLDB.
- Xophmeister 12y agoRecursive CTEs are part of the SQL:1999 standard and actually make SQL into Turing complete language. I didn't realise SQLite had implemented CTEs, let alone recursive ones...I'll have to play :)
- benilov 12y agoDbFit (http://dbfit.github.io/dbfit/ http://dbfit.github.io/dbfit/) provides a more heavy-weight, but much more scalable alternative to raw SQL for testing CTEs.
- j_s 12y agoIn SQL Server, CTEs eventually slow down then temp tables win because they can have indexes.