兩年內發票存在時按年份計算總計

Question

因此，我期望在兩年內每個客戶都有發票存在的總髮票。所以，我有

SELECT  Sum((tbl_invoice_details.quantity 
       - ifnull(tbl_invoice_details.quantity_returned, 0) 
       ) * tbl_invoice_details.price) AS dollarsSold, 
      tbl_customers.NAME, 
      cust_ID AS customer_id, 
      YEAR (tbl_invoice.invoice_date) AS invoiceYear 
FROM  `tbl_invoice_details` 
INNER JOIN `tbl_invoice` 
ON   `tbl_invoice_details`.`invoice_ID` = `tbl_invoice`.`invoice_ID` 
INNER JOIN `tbl_customers` 
ON   `tbl_customers`.`customer_ID` = `tbl_invoice`.`cust_ID` 
WHERE  MONTH (`invoice_date`) = '2' 
AND  (YEAR (`invoice_date`) = '2017' 
      OR 
      YEAR (`invoice_date`) = '2016') 
AND EXISTS (SELECT * 
      FROM tbl_invoice 
      WHERE cust_ID = customer_id 
      AND MONTH (`invoice_date`) = '2' 
      AND YEAR (`invoice_date`) = '2016') 
GROUP BY MONTH (tbl_invoice.invoice_date), 
      invoiceYear, 
      `tbl_customers`.`name`, 
      customer_id 
ORDER BY name 

那麼，如何將其限制爲同時具有2016和2017年我與EXISTS嘗試過，但是，這只是成功的一半在二月發票的客戶。

Answer 1

，以確保兩個發票存在的最好方法，是使用EXISTS兩次，一次爲2016和其他爲2017年

SELECT  Sum((tbl_invoice_details.quantity 
       - ifnull(tbl_invoice_details.quantity_returned, 0) 
       ) * tbl_invoice_details.price) AS dollarsSold, 
      tbl_customers.NAME, 
      cust_ID AS customer_id, 
      YEAR (tbl_invoice.invoice_date) AS invoiceYear 
FROM  `tbl_invoice_details` 
INNER JOIN `tbl_invoice` 
ON   `tbl_invoice_details`.`invoice_ID` = `tbl_invoice`.`invoice_ID` 
INNER JOIN `tbl_customers` 
ON   `tbl_customers`.`customer_ID` = `tbl_invoice`.`cust_ID` 
WHERE  MONTH (`invoice_date`) = '2' 
AND  YEAR (`invoice_date`) IN ('2016', '2017') 
AND EXISTS (SELECT 1 
      FROM tbl_invoice 
      WHERE cust_ID = customer_id 
      AND MONTH (`invoice_date`) = '2' 
      AND YEAR (`invoice_date`) = '2016') 
AND EXISTS (SELECT 1 
      FROM tbl_invoice 
      WHERE cust_ID = customer_id 
      AND MONTH (`invoice_date`) = '2' 
      AND YEAR (`invoice_date`) = '2017') 
GROUP BY MONTH (tbl_invoice.invoice_date), 
      invoiceYear, 
      `tbl_customers`.`name`, 
      customer_id 
ORDER BY name;