Dear all,

As you know I am relatively new to postgis and SQL and therefore  I have much 
to learn. However, I am facing a paper deadline and need to do some quick 
analysis of the data I have and I am struggling to figure out how best to 
pursue what I need to do.

I have a significant number of rasters which have double precision values.  
Without going into detail about what the rasters represent, I need to extract 
and sum values from one set of rasters in say table A based upon  values in 
another set of rasters in say table B  where the pixel value in the raster from 
Table B exceeds a threshold. Both tables are the same size (rasters are tiled) 
but I also need to figure out how I make sure the correct rasters are compared. 
 They have filenames like this rastervariable_10.tif, rastervariable_100.tif , 
presumably I need to use a logical expression to strip the numerical value (in 
this case this represents the year) and then order on that basis?

I can do this in QGIS one at a time but that is a little clumsy and rather time 
consuming.

If someone can just point me in the right direction I am sure I can figure out 
the rest for myself.

Apologies once more for asking what is probably a rather trivial question and 
yet again demonstrating my ignorance.

Many thanks

Darrel
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