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2011.05.27 / 16:46

where timestamp 처리

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timestamp 속성 값에서 date로 날짜 검색을 하는 경우
아래와 같이 처리한 쿼리가 많이 있는데
지금 날짜로 인덱스가 걸린 테이블은 A, B의 쿼리 결과가 차이가 별로 없는데
인덱스 잡으면 차이가 많이 나네요.
저는 쿼리를 변경하는게 번거로워서 함수로 한방(?)에 처리한다고 저렇게 했습니다만....
보니 많이들 A방법으로 쓰셨더라구요.
틈틈히 수정 될때 B의 방법으로 수정하시면 좋을듯 합니다.


A)
select
       count(*)       from
       a
      where
       DATE_FORMAT(reg_dt, '%Y/%m/%d') = '2010/03/01'

B)
select
       count(*)      from
a

      where
       reg_dt >= DATE_FORMAT( '2010/03/01' ,'%Y-%m-%d 00:00:00')
       AND reg_dt < DATE_FORMAT(DATE_ADD( '2010/03/01' , INTERVAL 1 DAY),'%Y-%m-%d 00:00:00')

 

 

Table 11.12. Date/Time Functions

Name Description
ADDDATE()(v4.1.1) Add time values (intervals) to a date value
ADDTIME()(v4.1.1) Add time
CONVERT_TZ()(v4.1.3) Convert from one timezone to another
CURDATE() Return the current date
CURRENT_DATE(), CURRENT_DATE Synonyms for CURDATE()
CURRENT_TIME(), CURRENT_TIME Synonyms for CURTIME()
CURRENT_TIMESTAMP(), CURRENT_TIMESTAMP Synonyms for NOW()
CURTIME() Return the current time
DATE_ADD() Add time values (intervals) to a date value
DATE_FORMAT() Format date as specified
DATE_SUB() Subtract a time value (interval) from a date
DATE()(v4.1.1) Extract the date part of a date or datetime expression
DATEDIFF()(v4.1.1) Subtract two dates
DAY()(v4.1.1) Synonym for DAYOFMONTH()
DAYNAME()(v4.1.21) Return the name of the weekday
DAYOFMONTH() Return the day of the month (0-31)
DAYOFWEEK() Return the weekday index of the argument
DAYOFYEAR() Return the day of the year (1-366)
EXTRACT() Extract part of a date
FROM_DAYS() Convert a day number to a date
FROM_UNIXTIME() Format UNIX timestamp as a date
GET_FORMAT()(v4.1.1) Return a date format string
HOUR() Extract the hour
LAST_DAY(v4.1.1) Return the last day of the month for the argument
LOCALTIME(), LOCALTIME Synonym for NOW()
LOCALTIMESTAMP, LOCALTIMESTAMP()(v4.0.6) Synonym for NOW()
MAKEDATE()(v4.1.1) Create a date from the year and day of year
MAKETIME(v4.1.1) MAKETIME()
MICROSECOND()(v4.1.1) Return the microseconds from argument
MINUTE() Return the minute from the argument
MONTH() Return the month from the date passed
MONTHNAME()(v4.1.21) Return the name of the month
NOW() Return the current date and time
PERIOD_ADD() Add a period to a year-month
PERIOD_DIFF() Return the number of months between periods
QUARTER() Return the quarter from a date argument
SEC_TO_TIME() Converts seconds to 'HH:MM:SS' format
SECOND() Return the second (0-59)
STR_TO_DATE()(v4.1.1) Convert a string to a date
SUBDATE() A synonym for DATE_SUB() when invoked with three arguments
SUBTIME()(v4.1.1) Subtract times
SYSDATE() Return the time at which the function executes
TIME_FORMAT() Format as time
TIME_TO_SEC() Return the argument converted to seconds
TIME()(v4.1.1) Extract the time portion of the expression passed
TIMEDIFF()(v4.1.1) Subtract time
TIMESTAMP()(v4.1.1) With a single argument, this function returns the date or datetime expression; with two arguments, the sum of the arguments
TO_DAYS() Return the date argument converted to days
UNIX_TIMESTAMP() Return a UNIX timestamp
UTC_DATE()(v4.1.1) Return the current UTC date
UTC_TIME()(v4.1.1) Return the current UTC time
UTC_TIMESTAMP()(v4.1.1) Return the current UTC date and time
WEEK() Return the week number
WEEKDAY() Return the weekday index
WEEKOFYEAR()(v4.1.1) Return the calendar week of the date (0-53)
YEAR() Return the year
YEARWEEK() Return the year and week

 

참고 http://dev.mysql.com/doc/refman/4.1/en/date-and-time-functions.html