MySQL built-in function learning notes

Tag: Date () now () pattern string intercept uppercase Max Ike string--

• Character functions
• numeric operators and functions
• comparison operators and functions
• Date-time functions
• Information functions
• Aggregation functions

One, character functions

• CONCAT (): Character connection
• Concat_ws (): Character join with specified delimiter
• Format (): Numeric formatting
• LOWER (): Convert to lowercase letter
• UPPER (): Convert to uppercase
• Left (): Gets the character
• Right (): Gets the character
• Length (): Gets the string length
• LTRIM (): Remove leading spaces
• RTRIM (): Delete subsequent spaces
• SUBSTRING (): String intercept
• ' Not ' like: pattern matching
• Replace (): string substitution

mysql> SELECT CONCAT (' SUN ', ' * ', ' YUE ', ' * ', ' RU '); +----------------------------------+| CONCAT (' SUN ', ' * ', ' YUE ', ' * ', ' RU ') |+----------------------------------+| Sun*yue*ru                       |+----------------------------------+1 row in Set (0.00 sec)
mysql> SELECT concat_ws (' & ', ' SUN ', ' YUE ', ' RU ');
+---------------------------------+
| Concat_ws (' & ', ' SUN ', ' YUE ', ' RU ') |
+---------------------------------+
| Sun&yue&ru |
+---------------------------------+
1 row in Set (0.00 sec)
Mysql> SELECT FORMAT (1223456.78,1);
+----------------------+
| FORMAT (1223456.78,1) |
+----------------------+
| 1,223,456.8 |
+----------------------+
1 row in Set (0.00 sec)
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Second, numeric operators and functions

• Ceil () into a rounding
• Div Integer rounding
• Floor () Rounding and rounding
• MOD take-up (modulo)
• ROUND () rounding
• TRUNCATE () Digital intercept

Third, comparison operators and functions

• [NOT] Between ... And ...
• [NOT] In ()
• is [NOT] NULL

Four, date Time function

• Now ()
• Curdate ()
• Curtime ()
• Date_add ()
• DATEDIFF ()
• Date_format ()

Http://www.w3school.com.cn/sql/sql_dates.asp

Five, information function

• CONNECTION_ID () connection ID
• Database () Current databases
• LAST_INSERT_ID () The ID number of the last inserted record
• User () Current users
• Version () Release information

Vi. Aggregation functions

• AVG ()
• COUNT ()
• MAX ()
• MIN ()
• SUM ()

MySQL built-in function learning notes