get the array value?

On Thu, Dec 25, 2008 at 7:15 AM, Charles.Hou <ivan(dot)hou(at)msa(dot)hinet(dot)net> wrote:
> name[] = { JOHN , ALEX , TEST ,""}
>
> SQL : select name from table1 where 'TEST' = any (name)
>
> return: { JOHN , ALEX , TEST }
>
> in this sql command, how can i get the index of 'TEST' is 3 ?

First of all. I assume the code above is meant to be pseudo-code, otherwise
this makes not much sense to me.

But if I understand you correctly, that you want to find the index (or position)
of a specific item in an array, then you have to write a function that iterates
over the array and returns the index.

This is a bad design however and it doesn't scale up well with large arrays.

A better approach is storing the array elements as rows in a table with an
index, which can be queried more efficiently.

For example:

CREATE TABLE records (
id SERIAL PRIMARY KEY
);

CREATE TABLE names (
record_id INTEGER REFERENCES records,
position INTEGER NOT NULL,
name TEXT NOT NULL,
UNIQUE (record_id, position)
);

This way you can easily search by doing something like

SELECT position FROM names
WHERE name = 'TEST';

Regards,
Victor Nawothnig