0
的導出字段列名
我們仍然可以通過使用派生列簡化這個查詢是另一個程序的輸入簡化查詢字符串通過重新使用MYSQL
$query = "SELECT table1.id,
COUNT(DISTINCT arr1.element) AS Arr1,
COUNT(DISTINCT arr2.element) AS Arr2,
COUNT(DISTINCT arr1.element) +
COUNT(DISTINCT arr2.element) AS tot,
(COUNT(DISTINCT arr1.element)/(COUNT(DISTINCT arr1.element)+COUNT(DISTINCT arr2.element)))*col3 AS c31,
(COUNT(DISTINCT arr2.element)/(COUNT(DISTINCT arr1.element)+COUNT(DISTINCT arr2.element)))*col3 AS c32
FROM table1
WHERE col2 = 'x'"
像這樣
$query = "SELECT table1.id,
COUNT(DISTINCT arr1.element) AS Arr1,
COUNT(DISTINCT arr2.element) AS Arr2,
COUNT(DISTINCT arr1.element) +
COUNT(DISTINCT arr2.element) AS tot,
(Arr1/tot)*col3 AS c31,
(Arr2/tot)*col3 AS c32
FROM table1
WHERE col2 = 'x'"
感謝