Php 减去1个查询'；s来自另一个查询的结果'；s结果

问题1：

问题2：

我想将查询1的

sum（quantity）

减去查询2的

sum（quantity）

请告诉我子问题的答案

    select q1_sum-q2_sum
    from( SELECT sum(quantity) as q1_sum
FROM `tbl_stock` 
WHERE item_id = '4' 
  AND div_id = '1' 
  AND internal_reel_no = 'DP1000585' 
  AND txn_type IN ('IN')
GROUP BY div_id, item_id, txn_type
    cross join
    SELECT sum(quantity) as q2_sum
FROM `tbl_stock` 
WHERE item_id = '4' 
  AND div_id = '1' 
  AND internal_reel_no = 'DP1000585' 
  AND txn_type IN ('IN')
GROUP BY div_id, item_id, txn_type
)

子查询

    select q1_sum-q2_sum
    from( SELECT sum(quantity) as q1_sum
FROM `tbl_stock` 
WHERE item_id = '4' 
  AND div_id = '1' 
  AND internal_reel_no = 'DP1000585' 
  AND txn_type IN ('IN')
GROUP BY div_id, item_id, txn_type
    cross join
    SELECT sum(quantity) as q2_sum
FROM `tbl_stock` 
WHERE item_id = '4' 
  AND div_id = '1' 
  AND internal_reel_no = 'DP1000585' 
  AND txn_type IN ('IN')
GROUP BY div_id, item_id, txn_type
)

我会尝试：

SELECT 
    sum(case when txn_type = 'IN' then quantity else 0 end) 
    - sum(case when txn_type = 'IS' then quantity else 0 end) 
FROM `tbl_stock` 
WHERE item_id = '4' 
  AND div_id = '1' 
  AND internal_reel_no = 'DP1000585' 
  AND txn_type IN ('IN','IS')
GROUP BY div_id, item_id

注意：这将在MSSQL中工作-您必须在MySQL中尝试它

我将尝试：

SELECT 
    sum(case when txn_type = 'IN' then quantity else 0 end) 
    - sum(case when txn_type = 'IS' then quantity else 0 end) 
FROM `tbl_stock` 
WHERE item_id = '4' 
  AND div_id = '1' 
  AND internal_reel_no = 'DP1000585' 
  AND txn_type IN ('IN','IS')
GROUP BY div_id, item_id

---

注意：这将在MSSQL中起作用-您必须在MySQL中尝试它，这里有另一个选项，它更通用，不涉及任何原始查询逻辑：

SELECT sum(quantity) INTO @sum1
FROM `tbl_stock` 
WHERE item_id = '4' 
  AND div_id = '1' 
  AND internal_reel_no = 'DP1000585' 
  AND txn_type IN ('IN')
GROUP BY div_id, item_id, txn_type;

SELECT sum(quantity) INTO @sum2
FROM `tbl_stock` 
WHERE item_id = '4' 
  AND div_id = '1' 
  AND internal_reel_no = 'DP1000585' 
  AND txn_type IN ('IS')
GROUP BY div_id, item_id, txn_type;

SELECT @sum1- @sum2;

---

下面是另一个选项，它更一般，不涉及任何原始查询逻辑：

SELECT sum(quantity) INTO @sum1
FROM `tbl_stock` 
WHERE item_id = '4' 
  AND div_id = '1' 
  AND internal_reel_no = 'DP1000585' 
  AND txn_type IN ('IN')
GROUP BY div_id, item_id, txn_type;

SELECT sum(quantity) INTO @sum2
FROM `tbl_stock` 
WHERE item_id = '4' 
  AND div_id = '1' 
  AND internal_reel_no = 'DP1000585' 
  AND txn_type IN ('IS')
GROUP BY div_id, item_id, txn_type;

SELECT @sum1- @sum2;

它有（或可以用）2个子选项，但这是一个非常好的答案。它有（或可以用）2个子选项，但这是一个非常好的答案。

SELECT SUM( CASE WHEN txn_type = 'IN' THEN quantity
                 WHEN txn_type = 'IS' THEN -quantity
                 END
          ) AS result
FROM
  ( SELECT txn_type, SUM(quantity) AS quantity
    FROM tbl_stock 
    WHERE item_id = '4' 
      AND div_id = '1' 
      AND internal_reel_no = 'DP1000585' 
      AND txn_type IN ('IN', 'IS')
    GROUP BY div_id, item_id, txn_type
  ) AS grp