CODEWITHSUNDEEP
sqlamazon-redshift
CoderBeginner
CoderBeginner

Reputation: 837

How to fetch records using vertical columns

I need to fetch records between the date range given in two columns.

My Table structure is like:

CREATE TABLE shared
(
   id         integer         NOT NULL,
   product          varchar(50)     NOT NULL,
   parent_id  integer         NOT NULL,
   key_code         varchar(100)    NOT NULL,
   key_value        varchar(8000)
);

INSERT INTO shared
    (`id`, `product`, `parent_id`, 'key_code', 'key_value')
VALUES
    (1, 'a',1, 'start_date','1/7/2011'),
    (2, 'a', 1,'end_date','15/7/2011'),
    (3, 'a',1, 'type','Promotion'),
    (4, 'a',1,'plan', 'new'),
    (5, 'a',5, 'start_date','11/8/2012'),
    (6, 'a', 5,'end_date','15/8/2012'),
    (7, 'a',5, 'type','Promotion'),
    (8, 'a',5,'plan', 'new'),
    (9, 'b',9, 'start_date','15/09/2015'),
    (10, 'b', 9,'end_date','15/09/2016'),
    (11, 'b',9, 'type','Promotion'),
    (12, 'b',9,'plan', 'new'),
;

Now i want to fetch all the records between start date>='1/7/2011' to start_date<='15/8/2012' where product='a'.

The Query I tried is:

SELECT 
    *
FROM
    (SELECT   parent_id,
         product,
          MIN(CASE WHEN key_code = 'key_code' THEN key_value ELSE 'n/a' END) AS key_code,
          MIN(CASE WHEN key_code = 'start_date' THEN key_value ELSE 'n/a' END) AS start_date,
          MIN(CASE WHEN key_code = 'end_date' THEN key_value ELSE 'n/a' END) AS end_date,
          MIN(CASE WHEN key_code = 'type' THEN key_value ELSE 'n/a' END) AS type,
          MIN(CASE WHEN key_code = 'plan' THEN key_value ELSE 'n/a' END) AS plan,
FROM     shared
GROUP BY parent_id,
         product
ORDER BY parent_id) comp
WHERE
    start_date>= '01/12/2011'
        AND start_date <= '02/17/2011' and product='a';

I am getting records now, changed the date format.

But is there any way to optimize this query.? Like this will take time to execute when records are in numbers.

Upvotes: 1

Views: 295

Answers (1)

nbk
nbk

Reputation: 49373

Your dates have not the MySQL format, so they have to be converted,to be compared

With the MIN and MAX and your 'n/a, it is better to use NULL in the inner Select and in the outer assign the Value n/a if the value is NULL, ot or else you get n/qa even if there is data.

SELECT 
    *
FROM
    (SELECT 
        parent_id,
            product,
            MIN(CASE WHEN key_code = 'start_date' THEN key_value ELSE 'n/a' END) AS start_date,
            MIN(CASE WHEN key_code = 'end_date' THEN key_value ELSE 'n/a' END) AS end_date,
            MAX(CASE WHEN key_code = 'type' THEN key_value ELSE 'n/a' END) AS type,
            MAX(CASE WHEN key_code = 'plan' THEN key_value ELSE 'n/a' END) AS plan
    FROM
        shared
    GROUP BY parent_id , product
    ORDER BY parent_id) comp
WHERE
    TO_DATE(start_date, 'DD/MM/YYYY') >= '2011-01-12'
        AND TO_DATE(start_date, 'DD/MM/YYYY') <= '2011-07-17'
        AND product = 'a'
;

Thsi would give youz

 parent_id  product  start_date  end_date   type        plan
 1          a        1/7/2011    15/7/2011  Promotion   new

So STR:TO:DATE doesn't exist in AWS but it EXISTS a TO_Date Instead of IF you maust do A CASe when like in your query

Upvotes: 1

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