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I've been moved onto a new project which uses numerous VIEWS in MySQL (5.7) queries. From what I understand, Views in MySQL are not the most performant and shouldn't be used for the sake of saving a bit of typing. I'm trying to profile the performance so I have an idea of whether or not it's a bottleneck but I'm having trouble trying to unravel a view to it's underlying query.

I can see the SQL query for the view but then that SQL contains its own view lookup and there's a chain. Is there a way, ideally using MySQL WorkBench, to have the merged view outputted so I don't need to do it by hand? There can be chains of 4 or more views and my head is just confused trying to put the parentheses in the right places around the right SELECT...WHERE/JOIN queries and I'm sure there's a way to automate this.

Thanks

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I don't think there is a way to get the "merge", unless it is in the JSON; see below.

Meanwhile, run EXPLAIN SELECT ... and EXPLAIN FORMAT=JSON SELECT ... to see what it says. I think it will, with dubious clarity, tell you whether it is doing the "merge" or "materialization".

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  • Thanks for the reply. Unfortunately it's not there but there doesn't seem to be another way. Regardless, thanks for the FORMAT=JSON code, I haven't seen that before and could be useful for other purposes. – iso123 Feb 9 '17 at 9:48

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