笨查詢問題

Question

我有這個疑問：

$this->db->select('COUNT(tran_ID) AS count, CASE WHEN MONTH(days)>=4 THEN concat(YEAR(days), "-", YEAR(days)+1) ELSE concat(YEAR(days)-1, "-", YEAR(days)) END AS format_date,product_class AS saleCol'); 

我得到語法錯誤的

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'WHEN MONTH(days)>=4 THEN concat(YEAR(days), `"-"`, YEAR(days)+1) ELSE concat(YEA' at line 1 

SELECT COUNT(tran_ID) AS count, `CASE` WHEN MONTH(days)>=4 THEN concat(YEAR(days), `"-"`, YEAR(days)+1) ELSE concat(YEAR(days)-1, `"-"`, YEAR(days)) END AS format_date, `product_class` AS saleCol FROM (`transactions`) WHERE `trans_type` = 'E' AND `product_class` != '0' GROUP BY `format_date`, `product_class` 

Answer 1

嘗試此查詢，添加FALSE在SELECT語句中的第二個參數

$this->db->select(
        'COUNT(tran_ID) AS count, 
        CASE WHEN MONTH(days)>=4 THEN concat(YEAR(days), "-", YEAR(days)+1) 
        ELSE concat(YEAR(days)-1, "-", YEAR(days)) 
        END AS format_date, 
        product_class AS saleCol',FALSE);