Re: How do I insert and update into a table of arrays of composite types via a select command?

Thanks Tom - I saw how to do that for specified data, but I want to select
the elements from a table of composite and don't know how to do that. I
can't do insertions manually of each row separately! So how do I get
material from my table of composite values into my table of array values?

I am running postgresql 9.6.2.

On Wed, Oct 25, 2017 at 3:47 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

> Celia McInnis <celia(dot)mcinnis(at)gmail(dot)com> writes:
> > My first question is: HOW do I populate this table, at first with arrays
> > containing one element from the t_composite table?
> > I have tried various things with no success.
>
> You didn't say what you tried, but I imagine it was something like
>
> regression=# insert into t_array select array[row('a','b','c'),row('d'
> ,'e','f')];
> ERROR: column "data_array" is of type mytype[] but expression is of type
> record[]
> LINE 1: insert into t_array select array[row('a','b','c'),row('d','e...
> ^
> HINT: You will need to rewrite or cast the expression.
>
> Like it says, you need a cast. You can either cast the array elements
> individually:
>
> regression=# insert into t_array select array[row('a','b','c')::
> mytype,row('d','e','f')::mytype];
> INSERT 0 1
>
> or just cast the whole ARRAY[] construct:
>
> regression=# insert into t_array select array[row('a','b','c'),row('d'
> ,'e','f')]::mytype[];
> INSERT 0 1
>
> although I think the latter only works in relatively late-model
> Postgres, and it might make parsing a bit slower too.
>
> regards, tom lane
>