mysql - 将 UPDATE 语句转换为 SELECT 语句

Question

以下语句更新名为“test”的表中的列。

UPDATE test AS t
INNER JOIN test AS q ON(
    q.ptime = t.ptime
)
SET t.slope_Percentile =(
    (
        SELECT
            count(*)
        FROM
            (
                SELECT
                    *
                FROM
                    test
            )AS t1
        WHERE
            t1.slope < t.slope
    )* 100 /(
        SELECT
            count(*)
        FROM
            (
                SELECT
                    *
                FROM
                    test
            ) AS tz
    )
);

我不想更新列，而是希望收到一个 SELECT 语句，该语句提供每行的读数(如果它是 UPDATE 语句，则会更新)。

有关表的性质和代码目标的更多信息(如果需要)在此处: Efficient assignment of percentile/rank in MYSQL

Answer 1

SELECT t.ptime,
( 
    ( 
        SELECT 
            count(*) 
        FROM 
            ( 
                SELECT 
                    * 
                FROM 
                    test 
            )AS t1 
        WHERE 
            t1.slope < t.slope 
    )* 100 /( 
        SELECT 
            count(*) 
        FROM 
            ( 
                SELECT 
                    * 
                FROM 
                    test 
            ) AS tz 
    ) 
)  AS slope_Percentile
 FROM test AS t 
--INNER JOIN test AS q ON
--q.ptime = t.ptime