STR_TO_DATE MySQL 5.5 和 MySQL 5.6 之间的差异

Question

SQL returns MySQL 5.5 中的 DATE 但 MySQL 5.6 中的 NULL。为什么？

select date(STR_TO_DATE('2015-01', '%Y-%m')) + INTERVAL 1 DAY;

这是 SQL Fiddle MySQL 5.5 and 5.6。 STR_TO_DATE returns 两个实例中的日期。使用 DATE 转换结果有效。尝试添加 INTERVAL 时出现问题。我在STR_TO_DATE(...)或DATE(STR_TO_DATE(...))上加一个INTERVAL都没有关系，结果是一样的。但是，删除 STR_TO_DATE 使其工作。

select
    STR_TO_DATE('2015-01', '%Y-%m') as same_a1,
    STR_TO_DATE('2015-01-01', '%Y-%m') as same_a2,
    STR_TO_DATE('2015-01', '%Y-%m-%d') as same_a3,
    STR_TO_DATE('2015-01-01', '%Y-%m-%d') as same_a4,
    date(STR_TO_DATE('2015-01', '%Y-%m')) as same_b1,
    date(STR_TO_DATE('2015-01-01', '%Y-%m')) as same_b2,
    date(STR_TO_DATE('2015-01', '%Y-%m-%d')) as same_b3,
    date(STR_TO_DATE('2015-01-01', '%Y-%m-%d')) as same_b4,
    STR_TO_DATE('2015-01', '%Y-%m') + INTERVAL 1 DAY as same_c1,
    STR_TO_DATE('2015-01-01', '%Y-%m') + INTERVAL 1 DAY as same_c2,
    STR_TO_DATE('2015-01', '%Y-%m-%d') + INTERVAL 1 DAY as same_c3,
    STR_TO_DATE('2015-01-01', '%Y-%m-%d') + INTERVAL 1 DAY as same_c4,
    date(STR_TO_DATE('2015-01', '%Y-%m')) + INTERVAL 1 DAY as different_d1,
    date(STR_TO_DATE('2015-01-01', '%Y-%m')) + INTERVAL 1 DAY as different_d2,
    date(STR_TO_DATE('2015-01', '%Y-%m-%d')) + INTERVAL 1 DAY as different_d3,
    date(STR_TO_DATE('2015-01-01', '%Y-%m-%d')) + INTERVAL 1 DAY as same_d4,
    date('2015-01') + INTERVAL 1 DAY as same_e1,
    date('2015-01-01') + INTERVAL 1 DAY as same_e2
;

我搜索了发行说明，但找不到任何内容。到底是怎么回事？这是一个已知的变化吗？错误？

Answer 1

这是一个已知的变化，无意中引入了版本 5.1.59, 5.5.16 and 5.6.3 (but was then rolled back in versions 5.1.62 and 5.5.21；它保留在 5.6 行中):

Incompatible Change: Handling of a date-related assertion was modified.

However, a consequence of this change is that several functions become more strict when passed a DATE() function value as their argument and reject incomplete dates with a day part of zero. These functions are affected: CONVERT_TZ(), DATE_ADD(), DATE_SUB(), DAYOFYEAR(), LAST_DAY(), TIMESTAMPDIFF(), TO_DAYS(), TO_SECONDS(), WEEK(), WEEKDAY(), WEEKOFYEAR(), YEARWEEK(). Because this changes date-handling behavior in General Availability-status series (MySQL 5.1 and 5.5), it was reverted in 5.1.62 and 5.5.21. The change is retained in MySQL 5.6.

References: See also Bug #13458237.

您受到了影响，因为 + INTERVAL 符号只是 DATE_ADD() 函数周围的语法糖。

STR_TO_DATE MySQL 5.5 和 MySQL 5.6 之间的差异

STR_TO_DATE discrepancy between MySQL 5.5 and MySQL 5.6

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