On Wed, Sep 29, 2010 at 07:08:22PM +0100, Thom Brown wrote: > Could someone explain why the following doesn't work? > > test=# PREPARE meow(unknown) AS > test-# SELECT $1 as meow; > ERROR: could not determine data type of parameter $1 > > The problem is that using PDO in PHP, prepared statements aren't > possible if values are used instead of columns in the select list. The type is always string for data that's sent; it's converted to an appropriate type when the destination of the parameter is determined. If you know the type, you can do PREPARE meow(text) AS SELECT $1 as meow; or PREPARE meow(unknown) AS SELECT $1::text as meow; You can also send a parameter as a specific type using the C interface, but that requires support from the language/library you're using. > This appears to be allowed for MySQL and SQL Server. I don't know how they handle that. Perhaps they try to read your mind. Perhaps PHP adds some kind of type conversion for types it knows for those two interfaces. Cheers, Peter -- http://sjamaan.ath.cx -- "The process of preparing programs for a digital computer is especially attractive, not only because it can be economically and scientifically rewarding, but also because it can be an aesthetic experience much like composing poetry or music." -- Donald Knuth -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
