Question

Iam使用SQLite这样的视图：

CREATE VIEW view_importaciones AS
      SELECT fecha_importacion, COUNT(DISTINCT(total)) - 1 AS total, COUNT(DISTINCT(errores)) -1 AS errores, estado FROM
        (
          SELECT fecha_importacion, id AS total, 0 as errores, estado FROM marcas WHERE parent_id = 0
          UNION
          SELECT fecha_importacion, 0 AS total, id as errores, estado FROM marcas WHERE valido = 'f' AND parent_id = 0
        ) AS importaciones GROUP BY fecha_importacion ORDER BY fecha_importacion

正如您所看到的， valido ='f'是硬编码的，但我将来需要使用MySQL，我使用execute方法运行此查询如何为每个创建正确的查询用于创建SQL视图的适配器“mysql，sqlite，postgresql等等。”

Answer 1

我找到了解决方案：

# First create the sql needed with the parameters, this way
# the query will change depeding on the database
sql = Marca.send(:construct_finder_sql, 
                  :select => "fecha_importacion, 0 AS total, id AS errores, estado",
                  :conditions => { :valido => false, :parent_id => 0}
                  :group => "marcas.fecha_importacion"
                 )

# Add the sql where needed
sql = "CREATE VIEW view_importaciones AS
  SELECT fecha_importacion, COUNT(DISTINCT(total)) - 1 AS total, COUNT(DISTINCT(errores)) -1 AS errores, estado FROM
    (
      SELECT fecha_importacion, id AS total, 0 as errores, estado FROM marcas WHERE parent_id = 0
      UNION
      #{sql}
    ) AS importaciones GROUP BY fecha_importacion ORDER BY fecha_importacion"
# Run the sql
execute(sql)

使用布尔值为rails中的SQL视图创建迁移

1 个答案: