使用额外的左表过滤器左连接性能

Question

嗨我想知道在左联盟中增加额外条件是否会提高性能。 示例代码如下。 我只需知道某些优惠的价格数据，但需要所有优惠数据。 只是想知道是否值得采用额外的连接条件来加速性能？

SELECT 
    * 
FROM
    OFFERS 
LEFT JOIN PRICE ON (
    PRICE.PH_SUBS_LINK_SK = ACTSUBS.PH_SUBS_LINK_SK and 
    PRICE.PRICE_END_DT= '09-09-9999' and
    OFFERS.PERCENT_VALUE >0 and 
    OFFERS.VALUE_OR_PERCENT = 'PERCENT' and 
    OFFERS.PRODUCT_OFFER_TYPE = 'RC' and 
    OFFERS.OFFER_STATUS_CODE in ('ACT','PTM')
    )

Answer 1

我建议更改以上代码：

    SELECT 
    * 
FROM
    OFFERS 
LEFT JOIN PRICE ON
    PRICE.PH_SUBS_LINK_SK = ACTSUBS.PH_SUBS_LINK_SK 
WHERE PRICE.PRICE_END_DT= '09-09-9999' and
    OFFERS.PERCENT_VALUE >0 and 
    OFFERS.VALUE_OR_PERCENT = 'PERCENT' and 
    OFFERS.PRODUCT_OFFER_TYPE = 'RC' and 
    OFFERS.OFFER_STATUS_CODE in ('ACT','PTM')

要提高性能，请在where语句中使用的字段创建索引。