提取物串

Question

我有這個疑問： -

select col_str, 
getVal,another_str,resultVal_str from tablename 

獲得的結果是這樣的：

col_str          getVal another_str    
'11,12,33,54,1,44'        '12' '9,5,4,8,7'    
'11,12,33,54,1,44,10,12,11,12,12'    '44' '9,5,4,8,7,6,3,5,2,4,2' 
'11,12,33,54,1,44'        '999' '9,5,4,8,7,4'    
'11,12,33'          '0'  '9,5,4'     
-----           ----  -----     
-----           ----  -----     
-----           ----  ----- 

col_str,getVal,another_str從表中傳來的列和列resultVal_str要根據計算其餘三列 邏輯resultVal_str -

查看第一次記錄getVal的值爲12並且col_str在位置編號2處具有12，則看到another_str中的位置編號2是5，因此resultVal_str是5等等。請看下圖：

col_str          getVal another_str    resultVal_str 
'11,12,33,54,1,44'        '12' '9,5,4,8,7'     5 
'11,12,33,54,1,44,10,12,11,12,12'    '44' '9,5,4,8,7,6,3,5,2,4,2'  6 
'11,12,33,54,1,44'        '999' '9,5,4,8,7,4'    0 
'11,12,33'          '0'  '9,5,4'      0 
-----           ----  -----      --- 
-----           ----  -----      --- 
-----           ----  -----      --- 

我怎麼能與得到的結果類似上面添加下一列resultVal_str？

Answer 1

首先您需要使用FIND_IN_SET函數在col_str中找到getVal的位置。

一旦你的位置，你可以找到使用SUBSTRING_INDEX功能another_str的resultVal從相同的位置：

SELECT SUBSTRING_INDEX(SUBSTRING_INDEX(another_str, 
         ",", (FIND_IN_SET(getVal, col_str))), 
         ",", - 1) AS resultVal_str 
FROM tablename; 

測試：

SET @getVal = '12', @col_str = '11,12,33,54,1,44', @another_str = '9,5,4,8,7'; 

SELECT SUBSTRING_INDEX(SUBSTRING_INDEX(@another_str, ",", (FIND_IN_SET(@getVal, @col_str))), ",", - 1) AS resultVal_str;