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How many levels can subqueries be nested in a FROM clause?
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How many levels can subqueries be nested in a FROM clause?
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syed shanu 9-Dec-14 1:12am    
? can you give more details and with example
Ankur\m/ 9-Dec-14 1:22am    
I am not sure of the limit but that shouldn't bother you. Don't create a query with a lot of nested queries, that's not a good practice and is hard to understand and maintain.
barneyman 9-Dec-14 1:29am    
seriously? googling the same question ( https://www.google.com.au/search?q=How+many+levels+can+subqueries+be+nested+in+a+FROM+clause&oq=How+many+levels+can+subqueries+be+nested+in+a+FROM+clause&aqs=chrome..69i57j69i64&sourceid=chrome&es_sm=122&ie=UTF-8 ) gives you 4 answers before it finds your question

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According to Microsoft the limit is 32 levels[^] for SQLServer.

Same limit in Oracle is 255[^].

If you're using some other DB you'll need to update your question and state what database you're using.
 
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/\jmot 9-Dec-14 4:31am    
+5
According to Microsoft there is no technical limit - http://technet.microsoft.com/en-us/library/ms177501(v=sql.105).aspx[^]
However with any new nested level you introduce a performance problem, so think carefully...
 
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Jörgen Andersson 9-Dec-14 4:14am    
I guess it depends on whether you decide to trust TechNet or MSDN.
Kornfeld Eliyahu Peter 9-Dec-14 4:28am    
In this case I have to - I never meet a single person that got so far to ask such a question :-)
Jörgen Andersson 9-Dec-14 5:30am    
I've seen the question before, I just can't imagine in what situation you would break the limit.
I'm working a lot with CTEs instead of subqueries, but I don't think I have ever reached more that six or seven level in depth.
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