MySQL change data set with table JOIN .. Is what I am asking possible? - mysql

Question

This is a complicated question, so please bear with me. I am using 3 different tables to make 1 result set. They are as follows:
customer_address_entity
entity_id | entity_type_id | attribute_set_id | increment_id | parent_id | create_at | update_at | is_active
customer_entity_int
value_id | entity_type_id | attribute_id | entity_id | value
customer_address_entity_varchar
value_id | entity_type_id | attribute_id | entity_id | value
Ok, so now you have the structure, here is my SQL call I have built so far:
SELECT CAE.entity_id,
CEI.value AS default_entity_id,
CAEV.attribute_id,
CAEV.value
FROM customer_address_entity AS CAE
JOIN customer_entity_int AS CEI
ON CEI.entity_id = CAE.parent_id
AND CEI.attribute_id = '13'
JOIN customer_address_entity_varchar AS CAEV
ON CAEV.entity_id = CAE.entity_id
WHERE CAE.parent_id = '2328'
AND CAE.is_active = 1
This outputs the following example dataset:
ID default att value
'1567', '1567', '19', 'John'
'1567', '1567', '21', 'Doe'
'1567', '1567', '23', 'Johns Company'
'1567', '1567', '25', 'Johns City'
'1567', '1567', '26', 'Johns Country'
'1567', '1567', '27', 'Johns State'
'1567', '1567', '29', 'Johns Zip Code'
'1567', '1567', '30', 'Johns Phone'
'1567', '1567', '31', 'Johns Fax'
'1568', '1567', '19', 'Jane'
'1568', '1567', '21', 'Doe'
'1568', '1567', '23', 'Janes Company'
'1568', '1567', '25', 'Janes City'
'1568', '1567', '26', 'Janes Country'
'1568', '1567', '27', 'Janes State'
'1568', '1567', '29', 'Janes Zip'
'1568', '1567', '30', 'Janes Phone'
'1568', '1567', '31', 'Janes Fax'
'1569', '1567', '19', 'Frank'
'1569', '1567', '21', 'Frunz'
'1569', '1567', '23', 'Franks Company'
'1569', '1567', '25', 'Franks City'
'1569', '1567', '26', 'Franks Country'
'1569', '1567', '27', 'Franks State'
'1569', '1567', '29', 'Franks Zip'
'1569', '1567', '30', 'Franks Phone'
'1569', '1567', '31', 'Franks Fax'
The final part of this code, I would like to create X number (in this case 3) of ROWS based on the number UNIQUE entity_id (Column 1 in returned data set ie .1567,1568 and 1569). The intended end result being:
'1567', '1567', 'John', 'Doe', 'Johns Company', 'Johns City', 'Johns State', 'Johns Zip Code', 'Johns Phone', 'Johns Fax'
'1568', '1567', 'Jane', 'Doe', 'Janes Company', ... etc
'1569', '1567', 'Frank', 'Franz', 'Franks Comapny', ... etc
Is this even possible?
EDIT Thanks to Gordon Linoff -- The answer is elegant and simple! I threw in a few edits of my own, but will be accepting Gordons answer and voting it up. Here are the edits I made, which work beautifully!!
select entity_id,
if(entity_id = default_entity_id, 'true', 'false') as default_entity,
max(case when attr = '19' then `value` end) as `FirstName`,
max(case when attr = '21' then `value` end) as `LastName`,
max(case when attr = '23' then `value` end) as `CompanyName`,
max(case when attr = '25' then `value` end) as `City`,
max(case when attr = '27' then `value` end) as `State`,
max(case when attr = '29' then `value` end) as `ZipCode`,
max(case when attr = '30' then `value` end) as `PhoneNumber`,
max(case when attr = '31' then `value` end) as `Fax`
from (SELECT CAE.entity_id, CEI.value AS default_entity_id, CAEV.attribute_id AS attr, CAEV.value
FROM customer_address_entity CAE
JOIN customer_entity_int CEI
ON CEI.entity_id = CAE.parent_id
AND CEI.attribute_id = '13'
JOIN customer_address_entity_varchar CAEV
ON CAEV.entity_id = CAE.entity_id
WHERE CAE.parent_id = '2328'
AND CAE.is_active = 1
) as t
group by entity_id

Answer 1

You can do this with a group by:
select entity_id,
MAX(default) as default,
max(case when att = '19' then value end) as FirstName,
max(case when att = '21' then value end) as LastName,
max(case when att = '23' then value end) as CompanyName,
max(case when att = '25' then value end) as City,
max(case when att = '27' then value end) as State,
max(case when att = '29' then value end) as ZipCode,
max(case when att = '30' then value end) as PhoneNumber,
max(case when att = '31' then value end) as Fax
from (SELECT CAE.entity_id, CEI.value AS default_entity_id, CAEV.attribute_id, CAEV.value
FROM customer_address_entity CAE
JOIN customer_entity_int CEI
ON CEI.entity_id = CAE.parent_id
AND CEI.attribute_id = '13'
JOIN customer_address_entity_varchar CAEV
ON CAEV.entity_id = CAE.entity_id
WHERE CAE.parent_id = '2328'
AND CAE.is_active = 1
) t
group by entity_id
This process is called pivoting and aggreagtion is one solution (some databases have a pivot keyword for this). This assumes that each value appears only once per entity. Also, if a value is not present, it will get the value NULL.

Answer 2

As #Gordon's answer points out, this is what is known as a PIVOT but MySQL does not have that function. In MySQL you can use an aggregate function with a CASE statement.
You can hard-code the values if they are all known:
SELECT CAE.entity_id,
CEI.value AS default_entity_id,
MAX(case when CAEV.attribute_id = 19 then CAEV.value else null end) FirstName,
MAX(case when CAEV.attribute_id = 21 then CAEV.value else null end) LastName,
MAX(case when CAEV.attribute_id = 23 then CAEV.value else null end) Company,
MAX(case when CAEV.attribute_id = 25 then CAEV.value else null end) City,
MAX(case when CAEV.attribute_id = 26 then CAEV.value else null end) Country,
MAX(case when CAEV.attribute_id = 27 then CAEV.value else null end) State,
MAX(case when CAEV.attribute_id = 29 then CAEV.value else null end) ZipCode,
MAX(case when CAEV.attribute_id = 30 then CAEV.value else null end) Phone,
MAX(case when CAEV.attribute_id = 31 then CAEV.value else null end) Fax
FROM customer_address_entity AS CAE
JOIN customer_entity_int AS CEI
ON CEI.entity_id = CAE.parent_id
AND CEI.attribute_id = '13'
JOIN customer_address_entity_varchar AS CAEV
ON CAEV.entity_id = CAE.entity_id
WHERE CAE.parent_id = '2328'
AND CAE.is_active = 1
GROUP BY CAE.entity_id, CEI.value;
Or you can use a prepared statement to implement dynamic sql. I would assume that you have a table that ties each attribute value to the name of the attribute:
SET #sql = NULL;
SELECT
GROUP_CONCAT(DISTINCT
CONCAT(
'max(case when CAEV.attribute_id = ''',
attribute_id,
''' then CAEV.value else null end) AS `',
attribute_id, '`'
)
) INTO #sql
FROM customer_address_entity_varchar;
SET #sql = CONCAT('SELECT CAE.entity_id,
CEI.value AS default_entity_id, ', #sql, '
FROM customer_address_entity AS CAE
JOIN customer_entity_int AS CEI
ON CEI.entity_id = CAE.parent_id
AND CEI.attribute_id = ''13' '
JOIN customer_address_entity_varchar AS CAEV
ON CAEV.entity_id = CAE.entity_id
WHERE CAE.parent_id = ''2328''
AND CAE.is_active = 1
GROUP BY CAE.entity_id, CEI.value');
PREPARE stmt FROM #sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;