How to query records for a period of time in mysql

Mysql method of querying records for a period of time: 1. Query records within N days, the code is [WHERE TO_DAYS(NOW()) - TO_DAYS (time field) <= N]; 2. Query today’s records, The code is [where date (time field) = date (now ())].

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mysql method of querying records for a period of time:

Records within 24 hours (i.e. 86400 seconds)

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PERIOD_DIFF(P1,P2)

Returns the number of months between periods P1 and P2. P1 and P2 should be specified in YYMM or YYYYMM. Note that the period parameters P1 and P2 are not date values:

mysql> SELECT PERIOD_DIFF(9802,199703);

-> 11

DATE_ADD(date,INTERVAL expr type )

DATE_SUB(date,INTERVAL expr type)

ADDDATE(date,INTERVAL expr type)

SUBDATE(date,INTERVAL expr type)

These functions perform arithmetic operations on dates. ADDDATE() and SUBDATE() are synonyms for DATE_ADD() and DATE_SUB() respectively. In MySQL 3.23, if the right side of the expression is a date value or a datetime field, you can use and - instead of DATE_ADD() and DATE_SUB() (example below). The date parameter is a DATETIME or DATE value specifying the beginning of a date. expr is an expression that specifies whether to add or subtract the interval value from the start date. expr is a string; it can be preceded by a "-" to represent a negative interval value. type is a keyword that indicates the format in which the expression is interpreted.

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