mysql - 1 つのクエリがデータをフェッチしていない場合、Mysql クエリが結合で機能しない

Question

以下の表から総在庫と利用可能な在庫を見つける必要があります。テーブル構造:

[Inventoryid] [inventory Type ] [issue status]
1              Mobile            Issued
2              Tablet            Not Issued
3              Mobile            Issued
4              Tablet            Not Issued

必要なアウトポットは

[Inventory Type] [Total Inventory]  [Available Inventory]
Mobile            2                  0
Tablet            2                  2

私に同じ質問をしてください。

Answer 1

SELECT  inventoryType,
        COUNT(*) totalInventory,
        SUM(issuestatus = 'not issued') available
FROM    tableName
GROUP   BY inventoryType

• SQLFiddleデモ

Answer 2

select inventory_type , count(*), sum(case when issue_Status = 'not issued' then 1
else 0 end) as status
From yourtable
group by inventory_type
;