How can those two SQL statements be combined into one? - mysql

Question

I wrote and would like to combine these 2 sql, one is based on results of another. I checked this post, but looks like its not results based. How could I achieve it ?
First sql:
SELECT
`potential`.*,
`customer`.`ID` as 'FID_customer'
FROM
`os_potential` as `potential`,
`os_customer` as `customer`
WHERE `potential`.`FID_author` = :randomID
AND `potential`.`converted` = 1
AND `potential`.`street` = `customer`.`street`
AND `potential`.`zip` = `customer`.`zip`
AND `potential`.`city` = `customer`.`city`;
Second sql:
SELECT
sum(`order`.`price_customer`) as 'Summe'
FROM
`os_order` as `order`,
`RESUTS_FROM_PREVIOUS_SQL_STATEMENT` as `results`
WHERE `order`.`FID_status` = 10
AND `results`.`FID_customer` = `order`.`FID_customer`;
I would like to get everything from first sql + the 'Summe' from second sql.
TABLES
1.Potentials:
+----+------------+-----------+--------+-----+------+
| ID | FID_author | converted | street | zip | city |
+----+------------+-----------+--------+-----+------+
2.Customers:
+----+--------+-----+------+
| ID | street | zip | city |
+----+--------+-----+------+
3.Orders:
+----+--------------+----------------+
| ID | FID_customer | price_customer |
+----+--------------+----------------+

Answer 1

SELECT p.*
, c.ID FID_customer
, o.summe
FROM os_potential p
JOIN os_customer c
ON c.street = p.street
AND c.zip = p.zip
AND c.city = p.city
JOIN
( SELECT FID_customer
, SUM(price_customer) Summe
FROM os_order
WHERE FID_status = 10
GROUP
BY FID_customer
) o
ON o.FID_customer = c.ID
WHERE p.FID_author = :randomID
AND p.converted = 1
;

Answer 2

You would just write a single query like this:
SELECT sum(o.price_customer) as Summe
FROM os_order o JOIN
os_potential p JOIN
os_customer c
ON p.street = c.street AND p.zip = c.zip AND p.city = c.city JOIN
os_order o2
ON o2.FID_customer = c.FID_customer
WHERE p.FID_author = :randomID AND p.converted = 1 AND
o2.FID_status = 10 ;
Notes:
Never use commas in the FROM clause. Always use explicit JOIN syntax with conditions in an ON clause.
Table aliases are easier to follow when they are short. Abbreviations for the table names is commonly used.
Backticks are only necessary when the table/column name needs to be escaped. Yours don't need to be escaped.

Answer 3

If the 1st query return 1 record per customer, then just simply join the 3 tables, keep the sum and use the group by clause:
SELECT
`potential`.*,
`customer`.`ID` as 'FID_customer',
sum(`order`.`price_customer`) as Summe
FROM
`os_potential` as `potential`
INNER JOIN
`os_customer` as `customer`
ON `potential`.`street` = `customer`.`street`
AND `potential`.`zip` = `customer`.`zip`
AND `potential`.`city` = `customer`.`city`
LEFT JOIN
`os_order` as `order`
ON `results`.`FID_customer` = `order`.`FID_customer`
AND `order`.`FID_status` = 10
WHERE `potential`.`FID_author` = :randomID
AND `potential`.`converted` = 1
GROUP BY `customer`.`ID`, <list all fields from potential table>
If the 1st query may return multiple records per customer, then you need to do the summing in a subquery:
SELECT
`potential`.*,
`customer`.`ID` as 'FID_customer',
`order`.Summe
FROM
`os_potential` as `potential`
INNER JOIN
`os_customer` as `customer`
ON `potential`.`street` = `customer`.`street`
AND `potential`.`zip` = `customer`.`zip`
AND `potential`.`city` = `customer`.`city`
LEFT JOIN
(SELECT FID_customer, sum(price_customer) as Summe
FROM `os_order`
WHERE FID_status=10
GROUP BY FID_customer
) as `order`
ON `results`.`FID_customer` = `order`.`FID_customer`
WHERE `potential`.`FID_author` = :randomID
AND `potential`.`converted` = 1

Answer 4

I think you should use a subselect, but be careful with the number of results, it's not the best for performance.
You can do something like this:
SELECT n1, n2, (select count(1) from whatever_table) as n3, n4 from whatever_table
note that the subselect must return just 1 result, in other case you'll have an error