您可以使用CASE statement来执行此操作。

• 示例代码 *

SELECT 
      date,
      MAX(CASE WHEN item = 'Item 1' THEN value END) AS 'Item 1',
      MAX(CASE WHEN item = 'Item 2' THEN value END) AS 'Item 2',
      MAX(CASE WHEN item = 'Item 3' THEN value END) AS 'Item 3'
    FROM mytable
    GROUP BY date;

您的更新查询，

SELECT 
  tbl_addcolumn.quantity,  tbl_addcolumn.unit, tbl_addcolumn.item,  tbl_supplier.company_name,
  MAX(CASE WHEN tbl_supplierprice.currency = 'EGB Trading' THEN tbl_supplierprice.totalPrice END) AS 'EGB Trading',
  MAX(CASE WHEN tbl_supplierprice.currency = 'Goodluck Trading' THEN tbl_supplierprice.totalPrice END) AS 'Goodluck Trading',
  tbl_addcolumn.totalcost
FROM tbl_addcolumn
INNER JOIN tbl_supplierprice   ON tbl_addcolumn.id = tbl_supplierprice.itemName
INNER JOIN tbl_supplier  ON tbl_supplierprice.fk_supplierId = tbl_supplier.id 
WHERE tbl_supplier.pr_no = '2023-03-0001'  
GROUP BY 
  tbl_addcolumn.quantity,
  tbl_addcolumn.unit,
  tbl_addcolumn.item,
  tbl_supplier.company_name,
  tbl_addcolumn.totalcost
ORDER BY 
  tbl_addcolumn.item ASC;

让我知道反馈，如果这工作。