Using select into to set variable value : Set Value « Postgre SQL « PostgreSQL






Using select into to set variable value


postgres=#
postgres=# CREATE TABLE "editions" (
postgres(#      "isbn" text NOT NULL,
postgres(#      "book_id" integer,
postgres(#      "edition" integer,
postgres(#      "publisher_id" integer,
postgres(#      "publication" date,
postgres(#      "type" character(1),
postgres(#      CONSTRAINT "integrity" CHECK (((book_id NOTNULL) AND (edition NOTNULL))),
postgres(#      Constraint "pkey" Primary Key ("isbn")
postgres(# );
NOTICE:  CREATE TABLE / PRIMARY KEY will create implicit index "pkey" for table "editions"
CREATE TABLE
postgres=#
postgres=# insert into editions value('039480001X', 1608,  1,  59,  '1957-03-01', 'h');
postgres=# insert into editions value('0451160916', 7808,  1,  75,  '1981-08-01', 'p');
postgres=# insert into editions value('0394800753', 1590,  1,  59,  '1949-03-01', 'p');
postgres=# insert into editions value('0590445065', 25908, 1,  150, '1987-03-01', 'p');
postgres=# insert into editions value('0694003611', 1501,  1,  65,  '1947-03-04', 'p');
postgres=# insert into editions value('0679803335', 1234,  1,  102, '1922-01-01', 'p');
postgres=# insert into editions value('0760720002', 190,   1,  91,  '1868-01-01', 'p');
postgres=# insert into editions value('0394900014', 1608,  1,  59,  '1957-01-01', 'p');
postgres=# insert into editions value('0385121679', 7808,  2,  75,  '1993-10-01', 'h');
postgres=# insert into editions value('1885418035', 156,   1,  163, '1995-03-28', 'p');
postgres=# insert into editions value('0929605942', 156,   2,  171, '1998-12-01', 'p');
postgres=# insert into editions value('0441172717', 4513,  2,  99,  '1998-09-01', 'p');
postgres=# insert into editions value('044100590X', 4513,  3,  99,  '1999-10-01', 'h');
postgres=# insert into editions value('0451457994', 4267,  3,  101, '2000-09-12', 'p');
postgres=# insert into editions value('0451198492', 4267,  3,  101, '1999-10-01', 'h');
postgres=# insert into editions value('0823015505', 2038,  1,  62,  '1958-01-01', 'p');
postgres=# insert into editions value('0596000855', 41473, 2,  113, '2001-03-01', 'p');
postgres=#
postgres=# select * from editions;
 isbn | book_id | edition | publisher_id | publication | type
------+---------+---------+--------------+-------------+------
(0 rows)

postgres=#
postgres=#
postgres=#
postgres=# CREATE TABLE "stock" (
postgres(#      "isbn" text NOT NULL,
postgres(#      "cost" numeric(5,2),
postgres(#      "retail" numeric(5,2),
postgres(#      "stock" integer,
postgres(#      Constraint "stock_pkey" Primary Key ("isbn")
postgres(# );
NOTICE:  CREATE TABLE / PRIMARY KEY will create implicit index "stock_pkey" for table "stock"
CREATE TABLE
postgres=#
postgres=#
postgres=# insert into stock values ('0385121679', 29.00, 36.95, 65);
INSERT 0 1
postgres=# insert into stock values ('039480001X', 30.00, 32.95, 31);
INSERT 0 1
postgres=# insert into stock values ('0394900014', 23.00, 23.95, 0);
INSERT 0 1
postgres=# insert into stock values ('044100590X', 36.00, 45.95, 89);
INSERT 0 1
postgres=# insert into stock values ('0441172717', 17.00, 21.95, 77);
INSERT 0 1
postgres=# insert into stock values ('0451160916', 24.00, 28.95, 22);
INSERT 0 1
postgres=# insert into stock values ('0451198492', 36.00, 46.95, 0);
INSERT 0 1
postgres=# insert into stock values ('0451457994', 17.00, 22.95, 0);
INSERT 0 1
postgres=# insert into stock values ('0590445065', 23.00, 23.95, 10);
INSERT 0 1
postgres=# insert into stock values ('0679803335', 20.00, 24.95, 18);
INSERT 0 1
postgres=# insert into stock values ('0694003611', 25.00, 28.95, 50);
INSERT 0 1
postgres=# insert into stock values ('0760720002', 18.00, 23.95, 28);
INSERT 0 1
postgres=# insert into stock values ('0823015505', 26.00, 28.95, 16);
INSERT 0 1
postgres=# insert into stock values ('0929605942', 19.00, 21.95, 25);
INSERT 0 1
postgres=# insert into stock values ('1885418035', 23.00, 24.95, 77);
INSERT 0 1
postgres=# insert into stock values ('0394800753', 16.00, 16.95, 4);
INSERT 0 1
postgres=#
postgres=# select * FROM stock;
    isbn    | cost  | retail | stock
------------+-------+--------+-------
 0385121679 | 29.00 |  36.95 |    65
 039480001X | 30.00 |  32.95 |    31
 0394900014 | 23.00 |  23.95 |     0
 044100590X | 36.00 |  45.95 |    89
 0441172717 | 17.00 |  21.95 |    77
 0451160916 | 24.00 |  28.95 |    22
 0451198492 | 36.00 |  46.95 |     0
 0451457994 | 17.00 |  22.95 |     0
 0590445065 | 23.00 |  23.95 |    10
 0679803335 | 20.00 |  24.95 |    18
 0694003611 | 25.00 |  28.95 |    50
 0760720002 | 18.00 |  23.95 |    28
 0823015505 | 26.00 |  28.95 |    16
 0929605942 | 19.00 |  21.95 |    25
 1885418035 | 23.00 |  24.95 |    77
 0394800753 | 16.00 |  16.95 |     4
(16 rows)

postgres=#
postgres=# drop function stock_amount(integer, integer);
DROP FUNCTION
postgres=#
postgres=# -- Using the IF/THEN statement
postgres=#
postgres=# CREATE FUNCTION stock_amount (integer, integer) RETURNS integer AS '
postgres'#   DECLARE
postgres'#      -- Declare aliases for function arguments.
postgres'#     b_id ALIAS FOR $1;
postgres'#     b_edition ALIAS FOR $2;
postgres'#      -- Declare variable to store the ISBN number.
postgres'#     b_isbn TEXT;
postgres'#      -- Declare variable to store the stock amount.
postgres'#     stock_amount INTEGER;
postgres'#   BEGIN
postgres'#     SELECT INTO b_isbn isbn FROM editions WHERE
postgres'#       book_id = b_id AND edition = b_edition;
postgres'#
postgres'#     IF b_isbn IS NULL THEN
postgres'#       RETURN -1;
postgres'#     END IF;
postgres'#
postgres'#     SELECT INTO stock_amount stock FROM stock WHERE isbn = b_isbn;
postgres'#
postgres'#     RETURN stock_amount;
postgres'#   END;
postgres'# ' LANGUAGE 'plpgsql';
CREATE FUNCTION
postgres=#
postgres=#
postgres=# SELECT stock_amount(7808,1);
 stock_amount
--------------
           -1
(1 row)

postgres=#
postgres=# drop table stock;
DROP TABLE
postgres=#
postgres=#
           
       








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