mse*_*man 7 mysql performance condition date query-performance
我想查找发生在特定日期的所有记录。
SELECT *
FROM table1
WHERE date(column) in ($date1, $date2, ...);
Run Code Online (Sandbox Code Playgroud)
但是,正如你们中的许多人一样,知道这种比较不适用于索引。所以,我想知道是否有一种简单的方法可以将此查询转换为以下查询的样式而无需太多努力(即:不使用外部工具)。
SELECT *
FROM table1
WHERE (column >= $date1 AND column < $date1 + interval 1 day)
OR (column >= $date2 AND column < $date2 + interval 1 day)
...
Run Code Online (Sandbox Code Playgroud)
所以优化器仍然可以使用索引。(我正在使用 MySQL,但 ANSI SQL 会很棒)
SELECT A.* FROM table1 A INNER JOIN
(
SELECT '2015-03-01' dtcolumn
UNION SELECT '2015-03-15'
UNION SELECT '2015-04-01'
UNION SELECT '2015-04-15'
UNION SELECT '2015-05-01'
) B ON
A.dtcolumn >= B.dtcolumn
AND A.dtcolumn < B.dtcolumn + INTERVAL 1 DAY;
Run Code Online (Sandbox Code Playgroud)
SELECT * FROM table1 WHERE
(column >= '2015-03-01' AND
column < '2015-03-01' + INTERVAL 1 DAY)
UNION
SELECT * FROM table1 WHERE
(column >= '2015-03-15' AND
column < '2015-03-15' + INTERVAL 1 DAY)
UNION
SELECT * FROM table1 WHERE
(column >= '2015-04-01' AND
column < '2015-04-01' + INTERVAL 1 DAY)
UNION
SELECT * FROM table1 WHERE
(column >= '2015-04-15' AND
column < '2015-04-15' + INTERVAL 1 DAY)
UNION
SELECT * FROM table1 WHERE
(column >= '2015-05-01' AND
column < '2015-05-01' + INTERVAL 1 DAY);
Run Code Online (Sandbox Code Playgroud)