Hi,
I have two tables: `tx` contains a set of named objects and then `tx_vals`
contain 0 to many possible values for those objects. I want to obtain a
table that contains all named objects in `tx` and one random value from
`tx_vals`. I think that has to be a left join to get the null values when a
tx object does not appear in tx_vals. I can obviously do this by finding
all the tx rows and then running a loop of queries on tx_vals, but I
wondered if there was a way to get the DAL to do it in one pass.
The table structure is:
db.define_table('tx', Field('name', 'string'))
db.tx.bulk_insert([{'name':'a'},
{'name':'b'},
{'name':'c'}])
db.define_table('tx_vals',
Field('tx_id', 'reference tx'),
Field('val', 'integer'))
db.tx_vals.bulk_insert([{'tx_id': 1, 'val':1},
{'tx_id': 1, 'val':2},
{'tx_id': 2, 'val':3},
{'tx_id': 2, 'val':4})
What I'm after is something that returns:
[('a', 1), ('b', 3), ('c', None)]
and where `a` will get 1 or 2 and `b` will get 3 or 4 randomly.
Thanks,
David
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