% wildcard in cpc_class_symbol

[jantonio.peces]

Code: Select all

(SELECT a.appln_id
FROM tls201_appln a
JOIN tls224_appln_cpc c ON a.appln_id = c.appln_id
WHERE 
cpc_class_symbol = 'F03B  13/12%' and earliest_publn_year > 2013)

returns 0 results but

Code: Select all

(SELECT a.appln_id
FROM tls201_appln a
JOIN tls224_appln_cpc c ON a.appln_id = c.appln_id
WHERE 
cpc_class_symbol = 'F03B  13/12' and earliest_publn_year > 2013)

returns 16 results!
The only difference is that I changed 'F03B 13/12%' to 'F03B 13/12'.

Am I doing something wrong?
Thanks in advance!

[Geert Boedt]

Just a small SQL syntax error:
SQL, wildcard characters (such as %, _ , [a-c]) are used with the SQL LIKE operator.

So it should be:
cpc_class_symbol LIKE 'F03B 13/12%'
or
cpc_class_symbol = 'F03B 13/12'

But in this case, the results will be identical because there are no other CPC classifications starting with 'F03B 13/12'
Be careful with SQL wild card approach !
Looking in detail at this classification itself:
http://worldwide.espacenet.com/classifi ... =F03B13/00 Observe that if you want to have all patents that include wave and tidal energy, you will need to adapt your query to include the specific classification codes such as F03B 13/26.
In this case the hierarchical CPC structure does not follow the numerical structure that can be covered with a simple SQL wild card use. To include tidal and wave energy you could use something like:
where (cpc_class_symbol = 'F03B13/12' or cpc_class_symbol like 'F03B 13/14%' or cpc_class_symbol like 'F03B 13/16%' or cpc_class_symbol like 'F03B 13/18%' or cpc_class_symbol like 'F03B 13/2%')

[jantonio.peces]

Thanks Geert, I always learn from you.

And what about using % wild character in the "in" syntax?

Code: Select all

where cpc_class_symbol in ('F03B13/12%', 'F03B 13/14%', 'F03B 13/16%' , 'F03B 13/18%' , 'F03B 13/2%')

Will I have the same issue ?
Thanks.