Markus Schaber wrote:
Hi, Fay,
Fay Du wrote:
Table cost
Id edge_id cost
1 30 101.4
2 30 null
3 40 500.2
4 40 null
5 45 300.7
6 45 null
I want to set cost value with same edge_id by same value. The existing
values are calculated by calling a function (calculate edge length). I
can calculate the value by same function, but the function was slow. I
wander if I can use update statement to set the second value with same
edge_id. Thanks in advance for your help.
It should go like:
UPDATE cost SET edge_id = (SELECT cost FROM cost innr WHERE innr.edge_id
= edge_id AND innr.cost is not null) WHERE cost is null;
HTH,
Marku
This is ok, but this is redundant, i guess. you should put edge_id and
cost into another table and use join to retrieve cost for each id.
put a key on edge_id, most likely a primary (unique) key.
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Gábriel Ákos
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