MySQL视图：在另一个计算字段中引用一个计算字段（按名称）

由于视图中不允许子查询，因此您需要通过创建多个视图来模拟它们。

例如，如果直接执行此查询，将解决您的问题：

SELECt     TotalCircles + TotalSquares AS TotalShapesFROM    (SELECt         BlueCirles + RedCircles AS TotalCircles,        BlueSquares + RedSquares AS TotalSquares    FROM        (SELECt 2 AS BlueCirles, 3 AS RedCircles, 4 AS BlueSquares, 5 AS RedSquares        ) AS shapes    ) as totals;

根据MySQL文档，视图在FROM子句中具有不能包含子查询的限制。要变通解决此限制并将该查询转换为视图，请将其分解为3个视图（每个子查询一个），最后一个给出所需的字段组合：

CREATE VIEW shapes ASSELECt    2 AS BlueCirles,    3 AS RedCircles,    4 AS BlueSquares,    5 AS RedSquares;CREATE VIEW totals ASSELECT     BlueCirles + RedCircles AS TotalCircles,    BlueSquares + RedSquares AS TotalSquaresFROM    shapes;CREATE VIEW result ASSELECt     TotalCircles + TotalSquares AS TotalShapesFROM    totals;SELECt * FROM result;