customerID
key1
value1

SELECT `customer`.*, `ca1`.`value1` AS `wedding_date`, `ca2`.`value1` AS `test`
FROM `customer`
LEFT JOIN `customer_attributes` AS `ca1` ON customer.customerID = ca1.customerID
LEFT JOIN `customer_attributes` AS `ca2` ON customer.customerID = ca2.customerID
WHERE (customer.customerID = '58029')
   AND (ca1.key1 = 'wedding_date')
   AND (ca2.key1 = 'test')

SELECT `customer`.*, `ca1`.`value1` AS `wedding_date`, `ca2`.`value1` AS `test`
FROM `customer`
LEFT JOIN `customer_attributes` AS `ca1` ON customer.customerID = ca1.customerID  AND ca1.key1='wedding_date'
LEFT JOIN `customer_attributes` AS `ca2` ON customer.customerID = ca2.customerID AND ca2.key1='test'
WHERE (customer.customerID = '58029')

SELECT `customer`.*, `ca1`.`value1` AS `wedding_date`, `ca2`.`value1` AS `test`
FROM `customer`
LEFT JOIN `customer_attributes` AS `ca1` ON customer.customerID = ca1.customerID AND ca1.key1 = 'wedding_date'
LEFT JOIN `customer_attributes` AS `ca2` ON customer.customerID = ca2.customerID AND ca2.key1 = 'test'
WHERE (customer.customerID = '58029')

SELECT `customer`.*, `ca1`.`value1` AS `wedding_date`, `ca2`.`value1` AS `test`
FROM `customer`
LEFT JOIN `customer_attributes` AS `ca1` ON customer.customerID = ca1.customerID
   AND (ca1.key1 = 'wedding_date')
LEFT JOIN `customer_attributes` AS `ca2` ON customer.customerID = ca2.customerID
   AND (ca2.key1 = 'test')
WHERE (customer.customerID = '58029')