PostgreSQL/Array/Array Column Select

Accessing two dimensional Arrays

postgres=# CREATE TABLE sal_emp (
postgres(#    name            text,
postgres(#    pay_by_quarter  integer[],
postgres(#    schedule        text[][]
postgres(# );
CREATE TABLE
postgres=#
postgres=# INSERT INTO sal_emp
postgres-#    VALUES ("Bill",
postgres(#    ARRAY[10000, 10000, 10000, 10000],
postgres(#    ARRAY[["meeting", "lunch"], ["training", "presentation"]]);
INSERT 0 1
postgres=#
postgres=# INSERT INTO sal_emp
postgres-#    VALUES ("Carol",
postgres(#    ARRAY[20000, 25000, 25000, 25000],
postgres(#    ARRAY[["breakfast", "consulting"], ["meeting", "lunch"]]);
INSERT 0 1
postgres=#
postgres=# -- Accessing Arrays
postgres=#
postgres=# SELECT name FROM sal_emp WHERE pay_by_quarter[1] <> pay_by_quarter[2];
 name
-------
 Carol
(1 row)
postgres=#
postgres=# SELECT * FROM sal_emp;
 name  |      pay_by_quarter       |                 schedule
-------+---------------------------+-------------------------------------------
 Bill  | {10000,10000,10000,10000} | {{meeting,lunch},{training,presentation}}
 Carol | {20000,25000,25000,25000} | {{breakfast,consulting},{meeting,lunch}}
(2 rows)
postgres=#
postgres=#
postgres=# drop table sal_emp;
DROP TABLE
postgres=#
postgres=#

Array Input and Output Syntax

postgres=#
postgres=# -- Array Input and Output Syntax
postgres=# SELECT 1 || ARRAY[2,3] AS array;
     array
---------------
 [0:2]={1,2,3}
(1 row)
postgres=#
postgres=#

Reference array element

postgres=#
postgres=#
postgres=# CREATE TABLE sal_emp (
postgres(#    name            text,
postgres(#    pay_by_quarter  integer[],
postgres(#    schedule        text[][]
postgres(# );
CREATE TABLE
postgres=#
postgres=# INSERT INTO sal_emp
postgres-#    VALUES ("Bill",
postgres(#    ARRAY[10000, 10000, 10000, 10000],
postgres(#    ARRAY[["meeting", "lunch"], ["training", "presentation"]]);
INSERT 0 1
postgres=#
postgres=# INSERT INTO sal_emp
postgres-#    VALUES ("Carol",
postgres(#    ARRAY[20000, 25000, 25000, 25000],
postgres(#    ARRAY[["breakfast", "consulting"], ["meeting", "lunch"]]);
INSERT 0 1
postgres=#
postgres=# -- Retrieves the third quarter pay of all employees:
postgres=#
postgres=# SELECT pay_by_quarter[3] FROM sal_emp;
 pay_by_quarter
----------------
          10000
          25000
(2 rows)
postgres=#
postgres=# SELECT * FROM sal_emp;
 name  |      pay_by_quarter       |                 schedule
-------+---------------------------+-------------------------------------------
 Bill  | {10000,10000,10000,10000} | {{meeting,lunch},{training,presentation}}
 Carol | {20000,25000,25000,25000} | {{breakfast,consulting},{meeting,lunch}}
(2 rows)
postgres=#
postgres=# drop table sal_emp;
DROP TABLE
postgres=#
postgres=#

Searching in Arrays

postgres=#
postgres=#
postgres=# CREATE TABLE sal_emp (
postgres(#    name            text,
postgres(#    pay_by_quarter  integer[],
postgres(#    schedule        text[][]
postgres(# );
CREATE TABLE
postgres=#
postgres=# INSERT INTO sal_emp
postgres-#    VALUES ("Bill",
postgres(#    ARRAY[10000, 10000, 10000, 10000],
postgres(#    ARRAY[["meeting", "lunch"], ["training", "presentation"]]);
INSERT 0 1
postgres=#
postgres=# INSERT INTO sal_emp
postgres-#    VALUES ("Carol",
postgres(#    ARRAY[20000, 25000, 25000, 25000],
postgres(#    ARRAY[["breakfast", "consulting"], ["meeting", "lunch"]]);
INSERT 0 1
postgres=#
postgres=# SELECT * FROM sal_emp;
 name  |      pay_by_quarter       |                 schedule
-------+---------------------------+-------------------------------------------
 Bill  | {10000,10000,10000,10000} | {{meeting,lunch},{training,presentation}}
 Carol | {20000,25000,25000,25000} | {{breakfast,consulting},{meeting,lunch}}
(2 rows)
postgres=# -- Searching in Arrays
postgres=# SELECT * FROM sal_emp WHERE pay_by_quarter[1] = 10000 OR
postgres-#                            pay_by_quarter[2] = 10000 OR
postgres-#                            pay_by_quarter[3] = 10000 OR
postgres-#                            pay_by_quarter[4] = 10000;
 name |      pay_by_quarter       |                 schedule
------+---------------------------+-------------------------------------------
 Bill | {10000,10000,10000,10000} | {{meeting,lunch},{training,presentation}}
(1 row)
postgres=#
postgres=#
postgres=# drop table sal_emp;
DROP TABLE
postgres=#

SELECT ARRAY[1,2] || ARRAY3,4 AS array

postgres=#
postgres=# SELECT ARRAY[1,2] || ARRAY[[3,4]] AS array;
          array
--------------------------
 [0:1][1:2]={{1,2},{3,4}}
(1 row)
postgres=#

Select array column by index

postgres=#
postgres=#
postgres=# CREATE TABLE book (id integer,titles text[]);
CREATE TABLE
postgres=#
postgres=# INSERT INTO book VALUES (102, "{"AAA\"s VVVV"}");
INSERT 0 1
postgres=#
postgres=# INSERT INTO book VALUES (103, "{"AAA", "VVVV"}");
INSERT 0 1
postgres=#
postgres=#
postgres=# SELECT titles[2] FROM book;
 titles
--------
 VVVV
(2 rows)
postgres=#
postgres=# SELECT titles[2] FROM book WHERE titles[2] IS NOT NULL;
 titles
--------
 VVVV
(1 row)
postgres=#
postgres=# drop table book;
DROP TABLE
postgres=#
postgres=#

Selecting array values with subscripts

postgres=#
postgres=# -- Selecting array values with subscripts
postgres=#
postgres=# CREATE TABLE book (id integer,titles text[]);
CREATE TABLE
postgres=#
postgres=# INSERT INTO book VALUES (102, "{"AAA\"s VVVV"}");
INSERT 0 1
postgres=#
postgres=# INSERT INTO book VALUES (103, "{"AAA", "VVVV"}");
INSERT 0 1
postgres=#
postgres=# SELECT titles[1] FROM book;
   titles
------------
 AAA"s VVVV
 AAA
(2 rows)
postgres=#
postgres=# drop table book;
DROP TABLE
postgres=#
postgres=#

Selecting entire array values

postgres=#
postgres=# -- Selecting entire array values
postgres=#
postgres=#
postgres=# CREATE TABLE book (id integer,titles text[]);
CREATE TABLE
postgres=#
postgres=# INSERT INTO book VALUES (102, "{"AAA\"s VVVV"}");
INSERT 0 1
postgres=#
postgres=# INSERT INTO book VALUES (103, "{"AAA", "VVVV"}");
INSERT 0 1
postgres=#
postgres=# SELECT titles FROM book;
     titles
----------------
 {"AAA"s VVVV"}
 {AAA,VVVV}
(2 rows)
postgres=#
postgres=# drop table book;
DROP TABLE
postgres=#
postgres=#

Selecting From a Multi-Dimensional Array

postgres=#
postgres=# CREATE TABLE authors (id integer,titles text[][]);
CREATE TABLE
postgres=#
postgres=# INSERT INTO authors
postgres-#              VALUES (102,
postgres(#              "{{"J T", "T S"},
postgres"#                {"C D", "G E"},
postgres"#                {"A D", "A L"}}");
INSERT 0 1
postgres=#
postgres=# -- Selecting From a Multi-Dimensional Array
postgres=#
postgres=# SELECT titles[1][1] AS author, titles[1][2] AS title FROM authors;
 author | title
--------+-------
 J T    | T S
(1 row)
postgres=#
postgres=# drop table authors;
DROP TABLE
postgres=#
postgres=#

Specify non-default array subscripts in an array literal

postgres=# -- Specify non-default array subscripts in an array literal
postgres=#
postgres=# SELECT f1[1][-2][3] AS e1, f1[1][-1][5] AS e2
postgres-# FROM (SELECT "[1:1][-2:-1][3:5]={{{1,2,3},{4,5,6}}}"::int[] AS f1) AS ss;
 e1 | e2
----+----
  1 |  6
(1 row)
postgres=#
postgres=#

Use array constant in select statement

postgres=#
postgres=# SELECT ARRAY[1,2,3+4];
  array
---------
 {1,2,7}
(1 row)

Using two dimension array

postgres=#
postgres=# SELECT ARRAY[[1,2],[3,4]];
     array
---------------
 {{1,2},{3,4}}
(1 row)
postgres=#