My mistake, what you want is CREATE AGGREGATE See http://h2database.com/html/grammar.html#create_aggregate http://h2database.com/javadoc/org/h2/api/AggregateFunction.html http://h2database.com/html/features.html#user_defined_functions
On Thu, Apr 18, 2013 at 11:13 PM, Brian Craft <[email protected]> wrote: > :) I have largish numerical data, like tens or hundreds of gigabytes. The > meta-data goes into relational tables, the raw data into varbinary chunks. > We could also use a document store for this, but I'm experimenting with > using varbinary. Using group_concat allows queries that return the meta-data > and the data together. If I don't do a group_concat then I have to issue two > queries and manage joining the second query with the first in application > code. > > If you have objections or suggestions, I'm very much interested. > > As a quick work-around, it appears I can cast it back to binary, like > cast(group_concat(x separator '') as binary). Not the best for performance, > most likely, though we're usually IO bound anyway. > > Alternatively I could try arrays of floats, but the group_concat behavior is > worse there: it is converted to ascii. > > Are there docs for CREATE ALIAS? I see some references in the text search > docs. It looks like it just sets up a binding to a java function. So would I > start by copying the group_concat function from the java source and using > CREATE ALIAS to set up a binding? > > > On Thursday, April 18, 2013 1:46:10 PM UTC-7, Noel Grandin wrote: >> >> Why would you want to do that? The whole point of binary columns is that >> they are opaque to the database and should not be manipulated by the >> database. >> >> But if you really want to you can always define your own function to do >> so. See the >> CREATE ALIAS >> command. >> >> >> On Thursday, 18 April 2013, Brian Craft wrote: >>> >>> It appears group_concat() converts binary columns to hex strings. Is that >>> correct? Is there any way to concat binary columns without them being >>> converted to hex? Would I have any more luck with arrays? Will group_concat >>> even work with array columns? >>> >>> -- >>> You received this message because you are subscribed to the Google Groups >>> "H2 Database" group. >>> To unsubscribe from this group and stop receiving emails from it, send an >>> email to [email protected]. >>> To post to this group, send email to [email protected]. >>> Visit this group at http://groups.google.com/group/h2-database?hl=en. >>> For more options, visit https://groups.google.com/groups/opt_out. >>> >>> > > -- > You received this message because you are subscribed to the Google Groups > "H2 Database" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/h2-database?hl=en. > For more options, visit https://groups.google.com/groups/opt_out. > > -- You received this message because you are subscribed to the Google Groups "H2 Database" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/h2-database?hl=en. For more options, visit https://groups.google.com/groups/opt_out.
