mysql - 计算不同表的总和值

Question

这是我的代码:

SELECT barang.id_brg, barang.nm_brg, jen_sat, nm_kat, SUM( IFNULL(  stok_brg.stok, 0 ) ) AS stok, IFNULL( laku, 0 ) AS laku
        FROM barang
        JOIN satuan ON barang.id_sat = satuan.id_sat
        JOIN kategori ON barang.id_kat = kategori.id_kat
        LEFT JOIN stok_brg ON barang.id_brg = stok_brg.id_brg
        LEFT JOIN (
        SELECT barang.id_brg, SUM( IFNULL( brg_laku.dibeli, 0 ) ) AS laku
        FROM barang, brg_laku
        WHERE barang.id_brg = brg_laku.id_brg
        GROUP BY barang.id_brg ASC
        ) AS brg_laku ON barang.id_brg = brg_laku.id_brg
        GROUP BY barang.id_brg ASC

我的代码预览:

问题是我想制作栏目 stok - laku 并将该结果作为栏目结果，你们能明白吗？抱歉，我的英语不好，所以我不知道该怎么说，希望你们能理解我，谢谢

Answer 1

看起来您想要区分列 stok 和 laku 之间的差异。如果是这样，请尝试以下操作:

select a.id_brg, a.nm_brg, a.jen_sat, a.nm_kat,a.stok,a.laku, (a.stok-a.laku) as difference
from (SELECT barang.id_brg, barang.nm_brg, jen_sat, nm_kat, SUM( IFNULL(  stok_brg.stok, 0 ) ) AS stok, IFNULL( laku, 0 ) AS laku
    FROM barang
    JOIN satuan ON barang.id_sat = satuan.id_sat
    JOIN kategori ON barang.id_kat = kategori.id_kat
    LEFT JOIN stok_brg ON barang.id_brg = stok_brg.id_brg
    LEFT JOIN (
    SELECT barang.id_brg, SUM( IFNULL( brg_laku.dibeli, 0 ) ) AS laku
    FROM barang, brg_laku
    WHERE barang.id_brg = brg_laku.id_brg
    GROUP BY barang.id_brg ASC
    ) AS brg_laku ON barang.id_brg = brg_laku.id_brg
    GROUP BY barang.id_brg ASC) as a;