Mysql，爲多個值選擇相同的列，不同的條件

Question

我無法弄清楚如何使用where子句創建多個選擇，以便爲我的名稱字段中的三個方案中的每一個都有一列。

查詢我現在是：

SELECT 
    pd_extrafields.packetDetailsId, 
    pd_extrafields.ex_value as Credit 
    FROM 
    pd_extrafields 
    where pd_extrafields.ex_title = "Credit,A,B,C,D,E,F" 

我怎麼能拉其他兩列到相同的查詢符合下列條件（基本上我想這三個查詢合併成一個，並保持柱名）：

SELECT 
    pd_extrafields.packetDetailsId, 
    pd_extrafields.ex_value as AccountNum 
    FROM 
    pd_extrafields 
    where pd_extrafields.ex_title = "Account#" 

&

SELECT 
    pd_extrafields.packetDetailsId, 
    pd_extrafields.ex_value as OrderStat 
    FROM 
    pd_extrafields 
    where pd_extrafields.ex_title = "New/Existing" 

Answer 1

ü se CASE。

select packetDetailsId, GROUP_CONCAT(Credit) AS Credit, GROUP_CONCAT(AccountNum) AS AccountNum, GROUP_CONCAT(OrderStat) AS OrderStat FROM 
(SELECT pd_extrafields.packetDetailsId, 
    CASE WHEN pd_extrafields.ex_title LIKE ('%Credit%') 
    THEN pd_extrafields.ex_value ELSE NULL END as Credit, 
    CASE WHEN pd_extrafields.ex_title LIKE ('%Account%') 
    THEN pd_extrafields.ex_value ELSE NULL END as AccountNum, 
    CASE WHEN pd_extrafields.ex_title LIKE ('%Existing%') 
    THEN pd_extrafields.ex_value ELSE NULL END as OrderStat 
    FROM pd_extrafields) AS TempTab GROUP BY packetDetailsId