Thank you for the prompt and clear answer. I work with a Mac (OS 10.4.3) and I used the PostgresApp to install it. I am a very primitive user of Postgres and think of it as Microsoft Access on Steroids. I access it via Aqua Data, Studio, but I don't think that makes any difference On 2/26/19, 8:04 PM, "Adrian Klaver" <adrian.klaver@xxxxxxxxxxx> wrote: On 2/26/19 5:51 PM, Martin Mueller wrote: > I run Postgres 10.5. I understand that there is something called > tablefunc and it includes a crosstab function. On Stack Overflow I learn > that you import this function. But from where and how? The Postgres > documentation is quite clear and intelligible to a retired English > professor like me, but there is nothing in the Postgres documentation > about how to do the import, and a search for ‘import modules’ yields > nothing. tablefunc is a contrib module so we need to know something information about your Postgres setup: 1) Your OS ? 2) How did you install Postgres? > > I tried to emulate a Stack overflow query that does what I want to do, > but got an error message saying that the crosstab function doesn’t > exist. I tried > > CREATEEXTENSION IFNOTEXISTStablefunc; > > but it did nothing. It doesn’t seem to work as import statements in > Python do The above depends on the module code actually existing where CREATE EXTENSION can find it. Whether the module exists and where it exists depends on the answers to the questions above. > > ----- > > Martin Mueller > Professor emeritus of English and Classics > > Northwestern University > -- Adrian Klaver adrian.klaver@xxxxxxxxxxx