DataGrid连接Access的快速分页法（3）——SQL语句的选用（降序）
三、降序
（1） @PageIndex <= @FirstIndex
SELECT TOP @PageSize @QueryFields
FROM @TableName
WHERE @Condition
ORDER BY @PrimaryKey DESC
（2） @FirstIndex < @PageIndex <= @MiddleIndex
SELECT TOP @PageSize @QueryFields
FROM @TableName
WHERE @PrimaryKey < (
SELECT MIN ( @PrimaryKey ) FROM (
SELECT TOP @PageSize * @PageIndex @PrimaryKey
FROM @TableName
WHERE @Condition
ORDER BY @PrimaryKey DESC
) TableA
) WHERE @Condition
ORDER BY @PrimaryKey DESC ****
（3） @MiddleIndex < @PageIndex < @LastIndex ****
SELECT * FROM (
SELECT TOP @PageSize @QueryFields
FROM @TableName
WHERE @PrimaryKey > (
SELECT MAX ( @PrimaryKey ) FROM (
SELECT TOP ( @RecordCount - @PageSize *( @PageIndex + 1 )) @PrimaryKey
FROM @TableName
WHERE @Condition
-- ORDER BY @PrimaryKey ASC
) TableA
) WHERE @Condition
-- ORDER BY @PrimaryKey ASC
) TableB
ORDER BY @PrimaryKey DESC
（4） @PageIndex >= @LastIndex
SELECT * FROM (
SELECT TOP ( @RecordCount - @PageSize * @LastIndex ) @QueryFields
FROM @TableName
WHERE @Condition
ORDER BY @PrimaryKey ASC
) TableA
ORDER BY @PrimaryKey DESC
四、总结
通过上面的讨论，相信大家应该看到了该分页方法的优势所在。在下一篇中，我将给大家一个动态生成上面 SQL 语句的类。
作者：黎波