On 19/06/2011 8:03 PM, Simon Slavin wrote:
> On 20 Jun 2011, at 12:58am, Lucas Cotta wrote:
>
>> I understand that for a query with a two tables join, SQLite will do a
>> nested loop join with these two tables.
>> But what about a query joining 5 tables?
>> It would be like this?:
>>
>> for(table1 lines){
>> for(table2 lines){
>> for(table3 lines){
>> ....
> You can use JOIN any number of times in a SELECT query. SQLite will work out
> an optimal way to access each table. You can speed things up a great deal by
> having useful INDEXes created.
IIRC sqlite does *not* do any join ordering optimizations and simply
runs them in whatever order the query specifies. This can have
unfortunate effects on runtime for some queries. Can anyone verify this?
Ryan
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