mysql - 如何从两个不同的表中获取特定列的总和并打印它

Question

select sum(Qty) AS QUANTITY
from purchase
where ItemName='$iname',
      sum(quantity) AS QUANTITY1
      from dispatch
      where ItemName='$iname';

如果我单独运行此查询，如果我运行上面的查询出现语法错误，我会得到结果

1064 - syntax error next to 'sum(Qty) AS QUANTITY1 from dispatch where ItemName='$iname'' Ã la ligne 1

Answer 1

作为列:

select  
    (select sum(Qty) AS QUANTITY from purchase where ItemName='$iname') AS QUANTITY, 
    (select sum(quantity) AS QUANTITY1 from dispatch where ItemName='$iname') AS QUANTITY1