--
-- ARRAYS
--
SELECT * FROM arrtest;
      a      |        b        |       c       |         d         |       e       |         f         |        g        
-------------+-----------------+---------------+-------------------+---------------+-------------------+-----------------
 {1,2,3,4,5} | {{{0,0},{1,2}}} | {}            | {}                |               | {}                | {}
 {11,12,23}  | {{3,4},{4,5}}   | {"foobar"}    | {{"elt1","elt2"}} | {"3.4","6.7"} | {"abc  ","abcde"} | {"abc","abcde"}
 {}          | {3,4}           | {"foo","bar"} | {"bar","foo"}     |               |                   | 
(3 rows)

SELECT arrtest.a[1],
          arrtest.b[1][1][1],
          arrtest.c[1],
          arrtest.d[1][1], 
          arrtest.e[0]
   FROM arrtest;
 a  | b |   c    |  d   | e 
----+---+--------+------+---
  1 | 0 |        |      |  
 11 |   | foobar | elt1 |  
    |   | foo    |      |  
(3 rows)

SELECT a[1], b[1][1][1], c[1], d[1][1], e[0]
   FROM arrtest;
 a  | b |   c    |  d   | e 
----+---+--------+------+---
  1 | 0 |        |      |  
 11 |   | foobar | elt1 |  
    |   | foo    |      |  
(3 rows)

SELECT a[1:3],
          b[1:1][1:2][1:2],
          c[1:2], 
          d[1:1][1:2]
   FROM arrtest;
     a      |        b        |       c       |         d         
------------+-----------------+---------------+-------------------
 {1,2,3}    | {{{0,0},{1,2}}} |               | 
 {11,12,23} |                 |               | {{"elt1","elt2"}}
            |                 | {"foo","bar"} | 
(3 rows)

-- returns three different results--
SELECT array_dims(arrtest.b) AS x;
        x        
-----------------
 [1:1][1:2][1:2]
 [1:2][1:2]
 [1:2]
(3 rows)

-- returns nothing 
SELECT *
   FROM arrtest
   WHERE a[1] < 5 and 
         c = '{"foobar"}'::_name;
 a | b | c | d | e | f | g 
---+---+---+---+---+---+---
(0 rows)

UPDATE arrtest
  SET a[1:2] = '{16,25}',
      b[1:1][1:1][1:2] = '{113, 117}', 
      c[1:1] = '{"new_word"}';
SELECT a[1:3],
          b[1:1][1:2][1:2],
          c[1:2], 
          d[1:1][2:2]
   FROM arrtest;
     a      |          b          |         c          |     d      
------------+---------------------+--------------------+------------
 {16,25,3}  | {{{113,117},{1,2}}} |                    | 
 {16,25,23} |                     |                    | {{"elt2"}}
            |                     | {"new_word","bar"} | 
(3 rows)