Mysql common functions

Mysql common functions

Common functions:

• Length () indicates the length of the returned bytes.
• Char_length () indicates the number of returned characters.
• Rand () indicates the random decimal place between 0 and 1.
• Round () indicates rounding.
• Date_add (now (), interval 10 day) indicates the date after 10 days.
• Date_add (now (), interval-10 day) indicates the date 10 days ago.
• Date_add (now (), interval 10 minute) indicates the time after 20 minutes.
• Date_add (now (), interval 10 week) indicates the date after 10 weeks
• Datediff () indicates the number of days between two dates.
• Timestampdiff (hour, now (), '2017-01-21 12:10:20 ') indicates that the time difference between two dates is returned.
• Date_format (now (), '% Y-% m-% d % H: % I: % s') indicates formatting a date and time.
• From_unixtime () indicates converting a timestamp into a date.
• Unix_timestamp () indicates converting a date into a timestamp.
• From_unixtime (timestamp, '% Y-% m-% d % H: % I: % s') indicates converting the timestamp into a date in the specified format.
• Concat () connection string.
• Repeat ('abc', 2) indicates that a string is repeated several times.
• Space (20) indicates the string that generates 20 spaces.
• Md5 (), sha (), sha1 (), password () indicates the encryption function.
• Supper () indicates converting the string to uppercase.
• Lower () indicates converting the string to lowercase.
• Left () indicates the length of the substring from the left.
• Right () indicates the length of the substring from the right.
• Mid () indicates the length of the substring from the specified position. The index starts from 1.
• Ifnull (expression 1, expression 2) If expression 1 is not empty, expression 1 is displayed; otherwise, expression 2 is displayed.
• If (expression, result 1, result 2) if the expression is true, result 1 is displayed; otherwise, result 2 is displayed.
• Uuid () indicates that 36 unique random strings are returned.
• Format () indicates formatting a number.
• Inet-aton () converts an IP address string to a number.
• Inet-ntoa () converts a number to an IP address.