Работа с запланированными событиями mysql
Содержание:
- SQL References
- SQL Working with Dates
- MySQL Advanced Functions
- Introduction to MySQL DATETIME data type
- Introduction to MySQL TIME data type
- SQL References
- SQL References
- Useful MySQL TIME functions
- SQL References
- SQL References
- Introduction to MySQL TIMESTAMP data type
- MySQL DATETIME functions
- SQL References
- Parameter Values
- More Examples
- MySQL DATETIME vs. TIMESTAMP
SQL References
SQL Keywords
ADD
ADD CONSTRAINT
ALTER
ALTER COLUMN
ALTER TABLE
ALL
AND
ANY
AS
ASC
BACKUP DATABASE
BETWEEN
CASE
CHECK
COLUMN
CONSTRAINT
CREATE
CREATE DATABASE
CREATE INDEX
CREATE OR REPLACE VIEW
CREATE TABLE
CREATE PROCEDURE
CREATE UNIQUE INDEX
CREATE VIEW
DATABASE
DEFAULT
DELETE
DESC
DISTINCT
DROP
DROP COLUMN
DROP CONSTRAINT
DROP DATABASE
DROP DEFAULT
DROP INDEX
DROP TABLE
DROP VIEW
EXEC
EXISTS
FOREIGN KEY
FROM
FULL OUTER JOIN
GROUP BY
HAVING
IN
INDEX
INNER JOIN
INSERT INTO
INSERT INTO SELECT
IS NULL
IS NOT NULL
JOIN
LEFT JOIN
LIKE
LIMIT
NOT
NOT NULL
OR
ORDER BY
OUTER JOIN
PRIMARY KEY
PROCEDURE
RIGHT JOIN
ROWNUM
SELECT
SELECT DISTINCT
SELECT INTO
SELECT TOP
SET
TABLE
TOP
TRUNCATE TABLE
UNION
UNION ALL
UNIQUE
UPDATE
VALUES
VIEW
WHERE
MySQL Functions
String Functions
ASCII
CHAR_LENGTH
CHARACTER_LENGTH
CONCAT
CONCAT_WS
FIELD
FIND_IN_SET
FORMAT
INSERT
INSTR
LCASE
LEFT
LENGTH
LOCATE
LOWER
LPAD
LTRIM
MID
POSITION
REPEAT
REPLACE
REVERSE
RIGHT
RPAD
RTRIM
SPACE
STRCMP
SUBSTR
SUBSTRING
SUBSTRING_INDEX
TRIM
UCASE
UPPER
Numeric Functions
ABS
ACOS
ASIN
ATAN
ATAN2
AVG
CEIL
CEILING
COS
COT
COUNT
DEGREES
DIV
EXP
FLOOR
GREATEST
LEAST
LN
LOG
LOG10
LOG2
MAX
MIN
MOD
PI
POW
POWER
RADIANS
RAND
ROUND
SIGN
SIN
SQRT
SUM
TAN
TRUNCATE
Date Functions
ADDDATE
ADDTIME
CURDATE
CURRENT_DATE
CURRENT_TIME
CURRENT_TIMESTAMP
CURTIME
DATE
DATEDIFF
DATE_ADD
DATE_FORMAT
DATE_SUB
DAY
DAYNAME
DAYOFMONTH
DAYOFWEEK
DAYOFYEAR
EXTRACT
FROM_DAYS
HOUR
LAST_DAY
LOCALTIME
LOCALTIMESTAMP
MAKEDATE
MAKETIME
MICROSECOND
MINUTE
MONTH
MONTHNAME
NOW
PERIOD_ADD
PERIOD_DIFF
QUARTER
SECOND
SEC_TO_TIME
STR_TO_DATE
SUBDATE
SUBTIME
SYSDATE
TIME
TIME_FORMAT
TIME_TO_SEC
TIMEDIFF
TIMESTAMP
TO_DAYS
WEEK
WEEKDAY
WEEKOFYEAR
YEAR
YEARWEEK
Advanced Functions
BIN
BINARY
CASE
CAST
COALESCE
CONNECTION_ID
CONV
CONVERT
CURRENT_USER
DATABASE
IF
IFNULL
ISNULL
LAST_INSERT_ID
NULLIF
SESSION_USER
SYSTEM_USER
USER
VERSION
SQL Server Functions
String Functions
ASCII
CHAR
CHARINDEX
CONCAT
Concat with +
CONCAT_WS
DATALENGTH
DIFFERENCE
FORMAT
LEFT
LEN
LOWER
LTRIM
NCHAR
PATINDEX
QUOTENAME
REPLACE
REPLICATE
REVERSE
RIGHT
RTRIM
SOUNDEX
SPACE
STR
STUFF
SUBSTRING
TRANSLATE
TRIM
UNICODE
UPPER
Numeric Functions
ABS
ACOS
ASIN
ATAN
ATN2
AVG
CEILING
COUNT
COS
COT
DEGREES
EXP
FLOOR
LOG
LOG10
MAX
MIN
PI
POWER
RADIANS
RAND
ROUND
SIGN
SIN
SQRT
SQUARE
SUM
TAN
Date Functions
CURRENT_TIMESTAMP
DATEADD
DATEDIFF
DATEFROMPARTS
DATENAME
DATEPART
DAY
GETDATE
GETUTCDATE
ISDATE
MONTH
SYSDATETIME
YEAR
Advanced Functions
CAST
COALESCE
CONVERT
CURRENT_USER
IIF
ISNULL
ISNUMERIC
NULLIF
SESSION_USER
SESSIONPROPERTY
SYSTEM_USER
USER_NAME
MS Access Functions
String Functions
Asc
Chr
Concat with &
CurDir
Format
InStr
InstrRev
LCase
Left
Len
LTrim
Mid
Replace
Right
RTrim
Space
Split
Str
StrComp
StrConv
StrReverse
Trim
UCase
Numeric Functions
Abs
Atn
Avg
Cos
Count
Exp
Fix
Format
Int
Max
Min
Randomize
Rnd
Round
Sgn
Sqr
Sum
Val
Date Functions
Date
DateAdd
DateDiff
DatePart
DateSerial
DateValue
Day
Format
Hour
Minute
Month
MonthName
Now
Second
Time
TimeSerial
TimeValue
Weekday
WeekdayName
Year
Other Functions
CurrentUser
Environ
IsDate
IsNull
IsNumeric
SQL OperatorsSQL Data TypesSQL Quick Ref
SQL Working with Dates
You can compare two dates easily if there is no time component involved!
Assume we have the following «Orders» table:
| OrderId | ProductName | OrderDate |
|---|---|---|
| 1 | Geitost | 2008-11-11 |
| 2 | Camembert Pierrot | 2008-11-09 |
| 3 | Mozzarella di Giovanni | 2008-11-11 |
| 4 | Mascarpone Fabioli | 2008-10-29 |
Now we want to select the records with an OrderDate of «2008-11-11» from the table above.
We use the following SELECT statement:
SELECT * FROM Orders WHERE OrderDate=’2008-11-11′
The result-set will look like this:
| OrderId | ProductName | OrderDate |
|---|---|---|
| 1 | Geitost | 2008-11-11 |
| 3 | Mozzarella di Giovanni | 2008-11-11 |
Now, assume that the «Orders» table looks like this (notice the time component in the «OrderDate» column):
| OrderId | ProductName | OrderDate |
|---|---|---|
| 1 | Geitost | 2008-11-11 13:23:44 |
| 2 | Camembert Pierrot | 2008-11-09 15:45:21 |
| 3 | Mozzarella di Giovanni | 2008-11-11 11:12:01 |
| 4 | Mascarpone Fabioli | 2008-10-29 14:56:59 |
If we use the same SELECT statement as above:
SELECT * FROM Orders WHERE OrderDate=’2008-11-11′
we will get no result! This is because the query is looking only for dates with no time portion.
Tip: To keep your queries simple and easy to maintain, do not allow time components in your dates!
MySQL Advanced Functions
| Function | Description |
|---|---|
| BIN | Returns a binary representation of a number |
| BINARY | Converts a value to a binary string |
| CASE | Goes through conditions and return a value when the first condition is met |
| CAST | Converts a value (of any type) into a specified datatype |
| COALESCE | Returns the first non-null value in a list |
| CONNECTION_ID | Returns the unique connection ID for the current connection |
| CONV | Converts a number from one numeric base system to another |
| CONVERT | Converts a value into the specified datatype or character set |
| CURRENT_USER | Returns the user name and host name for the MySQL account that the server used to authenticate the current client |
| DATABASE | Returns the name of the current database |
| IF | Returns a value if a condition is TRUE, or another value if a condition is FALSE |
| IFNULL | Return a specified value if the expression is NULL, otherwise return the expression |
| ISNULL | Returns 1 or 0 depending on whether an expression is NULL |
| LAST_INSERT_ID | Returns the AUTO_INCREMENT id of the last row that has been inserted or updated in a table |
| NULLIF | Compares two expressions and returns NULL if they are equal. Otherwise, the first expression is returned |
| SESSION_USER | Returns the current MySQL user name and host name |
| SYSTEM_USER | Returns the current MySQL user name and host name |
| USER | Returns the current MySQL user name and host name |
| VERSION | Returns the current version of the MySQL database |
Introduction to MySQL DATETIME data type
You use MySQL to store a value that contains both date and time. When you query data from a column, MySQL displays the value in the following format:
By default, values range from to .
A value uses 5 bytes for storage. In addition, a value can include a trailing fractional second up to microseconds with the format e.g., . When including the fractional second precision, values require more storage as illustrated in the following table:
For example, requires 8 bytes, 5 bytes for and 3 bytes for while requires only 6 bytes, 1 byte for the fractional second precision.
Note that before MySQL 5.6.4, values requires 8 bytes storage instead of 5 bytes.
Introduction to MySQL TIME data type
MySQL uses the format for querying and displaying a time value that represents a time of day, which is within 24 hours. To represent a time interval between two events, MySQL uses the format, which is larger than 24 hours.
To define a column, you use the following syntax:
For example, the following snippet defines a column named with data type.
A value ranges from to . In addition, a value can have fractional seconds part that is up to microseconds precision (6 digits). To define a column whose data type is with a fractional second precision part, you use the following syntax:
N is an integer that represents the fractional part, which is up to 6 digits.
The following snippet defines a column with data type including 3 digits of fractional seconds.
A value takes 3 bytes for storage. In case a value includes fractional second precision, it will take additional bytes based on the number of digits of the fractional second precision. The following table illustrates the storage required for fractional second precision.
| Fractional Second Precision | Storage (BYTES) |
| 1, 2 | 1 |
| 3, 4 | 2 |
| 5, 6 | 3 |
For example, and takes 3 bytes. and takes 4 bytes (3 + 1); and take 5 and 6 bytes.
SQL References
SQL Keywords
ADD
ADD CONSTRAINT
ALTER
ALTER COLUMN
ALTER TABLE
ALL
AND
ANY
AS
ASC
BACKUP DATABASE
BETWEEN
CASE
CHECK
COLUMN
CONSTRAINT
CREATE
CREATE DATABASE
CREATE INDEX
CREATE OR REPLACE VIEW
CREATE TABLE
CREATE PROCEDURE
CREATE UNIQUE INDEX
CREATE VIEW
DATABASE
DEFAULT
DELETE
DESC
DISTINCT
DROP
DROP COLUMN
DROP CONSTRAINT
DROP DATABASE
DROP DEFAULT
DROP INDEX
DROP TABLE
DROP VIEW
EXEC
EXISTS
FOREIGN KEY
FROM
FULL OUTER JOIN
GROUP BY
HAVING
IN
INDEX
INNER JOIN
INSERT INTO
INSERT INTO SELECT
IS NULL
IS NOT NULL
JOIN
LEFT JOIN
LIKE
LIMIT
NOT
NOT NULL
OR
ORDER BY
OUTER JOIN
PRIMARY KEY
PROCEDURE
RIGHT JOIN
ROWNUM
SELECT
SELECT DISTINCT
SELECT INTO
SELECT TOP
SET
TABLE
TOP
TRUNCATE TABLE
UNION
UNION ALL
UNIQUE
UPDATE
VALUES
VIEW
WHERE
MySQL Functions
String Functions
ASCII
CHAR_LENGTH
CHARACTER_LENGTH
CONCAT
CONCAT_WS
FIELD
FIND_IN_SET
FORMAT
INSERT
INSTR
LCASE
LEFT
LENGTH
LOCATE
LOWER
LPAD
LTRIM
MID
POSITION
REPEAT
REPLACE
REVERSE
RIGHT
RPAD
RTRIM
SPACE
STRCMP
SUBSTR
SUBSTRING
SUBSTRING_INDEX
TRIM
UCASE
UPPER
Numeric Functions
ABS
ACOS
ASIN
ATAN
ATAN2
AVG
CEIL
CEILING
COS
COT
COUNT
DEGREES
DIV
EXP
FLOOR
GREATEST
LEAST
LN
LOG
LOG10
LOG2
MAX
MIN
MOD
PI
POW
POWER
RADIANS
RAND
ROUND
SIGN
SIN
SQRT
SUM
TAN
TRUNCATE
Date Functions
ADDDATE
ADDTIME
CURDATE
CURRENT_DATE
CURRENT_TIME
CURRENT_TIMESTAMP
CURTIME
DATE
DATEDIFF
DATE_ADD
DATE_FORMAT
DATE_SUB
DAY
DAYNAME
DAYOFMONTH
DAYOFWEEK
DAYOFYEAR
EXTRACT
FROM_DAYS
HOUR
LAST_DAY
LOCALTIME
LOCALTIMESTAMP
MAKEDATE
MAKETIME
MICROSECOND
MINUTE
MONTH
MONTHNAME
NOW
PERIOD_ADD
PERIOD_DIFF
QUARTER
SECOND
SEC_TO_TIME
STR_TO_DATE
SUBDATE
SUBTIME
SYSDATE
TIME
TIME_FORMAT
TIME_TO_SEC
TIMEDIFF
TIMESTAMP
TO_DAYS
WEEK
WEEKDAY
WEEKOFYEAR
YEAR
YEARWEEK
Advanced Functions
BIN
BINARY
CASE
CAST
COALESCE
CONNECTION_ID
CONV
CONVERT
CURRENT_USER
DATABASE
IF
IFNULL
ISNULL
LAST_INSERT_ID
NULLIF
SESSION_USER
SYSTEM_USER
USER
VERSION
SQL Server Functions
String Functions
ASCII
CHAR
CHARINDEX
CONCAT
Concat with +
CONCAT_WS
DATALENGTH
DIFFERENCE
FORMAT
LEFT
LEN
LOWER
LTRIM
NCHAR
PATINDEX
QUOTENAME
REPLACE
REPLICATE
REVERSE
RIGHT
RTRIM
SOUNDEX
SPACE
STR
STUFF
SUBSTRING
TRANSLATE
TRIM
UNICODE
UPPER
Numeric Functions
ABS
ACOS
ASIN
ATAN
ATN2
AVG
CEILING
COUNT
COS
COT
DEGREES
EXP
FLOOR
LOG
LOG10
MAX
MIN
PI
POWER
RADIANS
RAND
ROUND
SIGN
SIN
SQRT
SQUARE
SUM
TAN
Date Functions
CURRENT_TIMESTAMP
DATEADD
DATEDIFF
DATEFROMPARTS
DATENAME
DATEPART
DAY
GETDATE
GETUTCDATE
ISDATE
MONTH
SYSDATETIME
YEAR
Advanced Functions
CAST
COALESCE
CONVERT
CURRENT_USER
IIF
ISNULL
ISNUMERIC
NULLIF
SESSION_USER
SESSIONPROPERTY
SYSTEM_USER
USER_NAME
MS Access Functions
String Functions
Asc
Chr
Concat with &
CurDir
Format
InStr
InstrRev
LCase
Left
Len
LTrim
Mid
Replace
Right
RTrim
Space
Split
Str
StrComp
StrConv
StrReverse
Trim
UCase
Numeric Functions
Abs
Atn
Avg
Cos
Count
Exp
Fix
Format
Int
Max
Min
Randomize
Rnd
Round
Sgn
Sqr
Sum
Val
Date Functions
Date
DateAdd
DateDiff
DatePart
DateSerial
DateValue
Day
Format
Hour
Minute
Month
MonthName
Now
Second
Time
TimeSerial
TimeValue
Weekday
WeekdayName
Year
Other Functions
CurrentUser
Environ
IsDate
IsNull
IsNumeric
SQL OperatorsSQL Data TypesSQL Quick Ref
SQL References
SQL Keywords
ADD
ADD CONSTRAINT
ALTER
ALTER COLUMN
ALTER TABLE
ALL
AND
ANY
AS
ASC
BACKUP DATABASE
BETWEEN
CASE
CHECK
COLUMN
CONSTRAINT
CREATE
CREATE DATABASE
CREATE INDEX
CREATE OR REPLACE VIEW
CREATE TABLE
CREATE PROCEDURE
CREATE UNIQUE INDEX
CREATE VIEW
DATABASE
DEFAULT
DELETE
DESC
DISTINCT
DROP
DROP COLUMN
DROP CONSTRAINT
DROP DATABASE
DROP DEFAULT
DROP INDEX
DROP TABLE
DROP VIEW
EXEC
EXISTS
FOREIGN KEY
FROM
FULL OUTER JOIN
GROUP BY
HAVING
IN
INDEX
INNER JOIN
INSERT INTO
INSERT INTO SELECT
IS NULL
IS NOT NULL
JOIN
LEFT JOIN
LIKE
LIMIT
NOT
NOT NULL
OR
ORDER BY
OUTER JOIN
PRIMARY KEY
PROCEDURE
RIGHT JOIN
ROWNUM
SELECT
SELECT DISTINCT
SELECT INTO
SELECT TOP
SET
TABLE
TOP
TRUNCATE TABLE
UNION
UNION ALL
UNIQUE
UPDATE
VALUES
VIEW
WHERE
MySQL Functions
String Functions
ASCII
CHAR_LENGTH
CHARACTER_LENGTH
CONCAT
CONCAT_WS
FIELD
FIND_IN_SET
FORMAT
INSERT
INSTR
LCASE
LEFT
LENGTH
LOCATE
LOWER
LPAD
LTRIM
MID
POSITION
REPEAT
REPLACE
REVERSE
RIGHT
RPAD
RTRIM
SPACE
STRCMP
SUBSTR
SUBSTRING
SUBSTRING_INDEX
TRIM
UCASE
UPPER
Numeric Functions
ABS
ACOS
ASIN
ATAN
ATAN2
AVG
CEIL
CEILING
COS
COT
COUNT
DEGREES
DIV
EXP
FLOOR
GREATEST
LEAST
LN
LOG
LOG10
LOG2
MAX
MIN
MOD
PI
POW
POWER
RADIANS
RAND
ROUND
SIGN
SIN
SQRT
SUM
TAN
TRUNCATE
Date Functions
ADDDATE
ADDTIME
CURDATE
CURRENT_DATE
CURRENT_TIME
CURRENT_TIMESTAMP
CURTIME
DATE
DATEDIFF
DATE_ADD
DATE_FORMAT
DATE_SUB
DAY
DAYNAME
DAYOFMONTH
DAYOFWEEK
DAYOFYEAR
EXTRACT
FROM_DAYS
HOUR
LAST_DAY
LOCALTIME
LOCALTIMESTAMP
MAKEDATE
MAKETIME
MICROSECOND
MINUTE
MONTH
MONTHNAME
NOW
PERIOD_ADD
PERIOD_DIFF
QUARTER
SECOND
SEC_TO_TIME
STR_TO_DATE
SUBDATE
SUBTIME
SYSDATE
TIME
TIME_FORMAT
TIME_TO_SEC
TIMEDIFF
TIMESTAMP
TO_DAYS
WEEK
WEEKDAY
WEEKOFYEAR
YEAR
YEARWEEK
Advanced Functions
BIN
BINARY
CASE
CAST
COALESCE
CONNECTION_ID
CONV
CONVERT
CURRENT_USER
DATABASE
IF
IFNULL
ISNULL
LAST_INSERT_ID
NULLIF
SESSION_USER
SYSTEM_USER
USER
VERSION
SQL Server Functions
String Functions
ASCII
CHAR
CHARINDEX
CONCAT
Concat with +
CONCAT_WS
DATALENGTH
DIFFERENCE
FORMAT
LEFT
LEN
LOWER
LTRIM
NCHAR
PATINDEX
QUOTENAME
REPLACE
REPLICATE
REVERSE
RIGHT
RTRIM
SOUNDEX
SPACE
STR
STUFF
SUBSTRING
TRANSLATE
TRIM
UNICODE
UPPER
Numeric Functions
ABS
ACOS
ASIN
ATAN
ATN2
AVG
CEILING
COUNT
COS
COT
DEGREES
EXP
FLOOR
LOG
LOG10
MAX
MIN
PI
POWER
RADIANS
RAND
ROUND
SIGN
SIN
SQRT
SQUARE
SUM
TAN
Date Functions
CURRENT_TIMESTAMP
DATEADD
DATEDIFF
DATEFROMPARTS
DATENAME
DATEPART
DAY
GETDATE
GETUTCDATE
ISDATE
MONTH
SYSDATETIME
YEAR
Advanced Functions
CAST
COALESCE
CONVERT
CURRENT_USER
IIF
ISNULL
ISNUMERIC
NULLIF
SESSION_USER
SESSIONPROPERTY
SYSTEM_USER
USER_NAME
MS Access Functions
String Functions
Asc
Chr
Concat with &
CurDir
Format
InStr
InstrRev
LCase
Left
Len
LTrim
Mid
Replace
Right
RTrim
Space
Split
Str
StrComp
StrConv
StrReverse
Trim
UCase
Numeric Functions
Abs
Atn
Avg
Cos
Count
Exp
Fix
Format
Int
Max
Min
Randomize
Rnd
Round
Sgn
Sqr
Sum
Val
Date Functions
Date
DateAdd
DateDiff
DatePart
DateSerial
DateValue
Day
Format
Hour
Minute
Month
MonthName
Now
Second
Time
TimeSerial
TimeValue
Weekday
WeekdayName
Year
Other Functions
CurrentUser
Environ
IsDate
IsNull
IsNumeric
SQL OperatorsSQL Data TypesSQL Quick Ref
Useful MySQL TIME functions
MySQL provides several useful temporal functions for manipulating data.
Getting to know the current time
To get the current time of the database server, you use the function. The function returns the current time value as a string ( ) or a numeric value ( ) depending on the context where the function is used.
The following statements illustrate the function in both string and numeric contexts:
Adding and Subtracting time from a TIME value
To add a value to another value, you use the function. To subtract a value from another value, you use the function.
The following statement adds and subtracts 2 hours 30 minutes to and from the current time.
In addition, you can use the function to get a difference between two values.
Formatting MySQL TIME values
Although MySQL uses when retrieving and displaying the a value, you can display the value in your preferred way using the function.
The function is like the function except that the function is used to format a value only.
See the following example.
In the time format string above:
- means two-digit hours from 0 to 12.
- means two-digit minutes from 0 to 60.
- means AM or PM.
To extract the hour, minute, and second from a value, you use , , and functions as follows:
Getting UTC time value
To get the UTC time, you use function as follows:
In this tutorial, we have been covered a lot about MySQL data type and some commonly used temporal functions for manipulating values.
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SQL References
SQL Keywords
ADD
ADD CONSTRAINT
ALTER
ALTER COLUMN
ALTER TABLE
ALL
AND
ANY
AS
ASC
BACKUP DATABASE
BETWEEN
CASE
CHECK
COLUMN
CONSTRAINT
CREATE
CREATE DATABASE
CREATE INDEX
CREATE OR REPLACE VIEW
CREATE TABLE
CREATE PROCEDURE
CREATE UNIQUE INDEX
CREATE VIEW
DATABASE
DEFAULT
DELETE
DESC
DISTINCT
DROP
DROP COLUMN
DROP CONSTRAINT
DROP DATABASE
DROP DEFAULT
DROP INDEX
DROP TABLE
DROP VIEW
EXEC
EXISTS
FOREIGN KEY
FROM
FULL OUTER JOIN
GROUP BY
HAVING
IN
INDEX
INNER JOIN
INSERT INTO
INSERT INTO SELECT
IS NULL
IS NOT NULL
JOIN
LEFT JOIN
LIKE
LIMIT
NOT
NOT NULL
OR
ORDER BY
OUTER JOIN
PRIMARY KEY
PROCEDURE
RIGHT JOIN
ROWNUM
SELECT
SELECT DISTINCT
SELECT INTO
SELECT TOP
SET
TABLE
TOP
TRUNCATE TABLE
UNION
UNION ALL
UNIQUE
UPDATE
VALUES
VIEW
WHERE
MySQL Functions
String Functions
ASCII
CHAR_LENGTH
CHARACTER_LENGTH
CONCAT
CONCAT_WS
FIELD
FIND_IN_SET
FORMAT
INSERT
INSTR
LCASE
LEFT
LENGTH
LOCATE
LOWER
LPAD
LTRIM
MID
POSITION
REPEAT
REPLACE
REVERSE
RIGHT
RPAD
RTRIM
SPACE
STRCMP
SUBSTR
SUBSTRING
SUBSTRING_INDEX
TRIM
UCASE
UPPER
Numeric Functions
ABS
ACOS
ASIN
ATAN
ATAN2
AVG
CEIL
CEILING
COS
COT
COUNT
DEGREES
DIV
EXP
FLOOR
GREATEST
LEAST
LN
LOG
LOG10
LOG2
MAX
MIN
MOD
PI
POW
POWER
RADIANS
RAND
ROUND
SIGN
SIN
SQRT
SUM
TAN
TRUNCATE
Date Functions
ADDDATE
ADDTIME
CURDATE
CURRENT_DATE
CURRENT_TIME
CURRENT_TIMESTAMP
CURTIME
DATE
DATEDIFF
DATE_ADD
DATE_FORMAT
DATE_SUB
DAY
DAYNAME
DAYOFMONTH
DAYOFWEEK
DAYOFYEAR
EXTRACT
FROM_DAYS
HOUR
LAST_DAY
LOCALTIME
LOCALTIMESTAMP
MAKEDATE
MAKETIME
MICROSECOND
MINUTE
MONTH
MONTHNAME
NOW
PERIOD_ADD
PERIOD_DIFF
QUARTER
SECOND
SEC_TO_TIME
STR_TO_DATE
SUBDATE
SUBTIME
SYSDATE
TIME
TIME_FORMAT
TIME_TO_SEC
TIMEDIFF
TIMESTAMP
TO_DAYS
WEEK
WEEKDAY
WEEKOFYEAR
YEAR
YEARWEEK
Advanced Functions
BIN
BINARY
CASE
CAST
COALESCE
CONNECTION_ID
CONV
CONVERT
CURRENT_USER
DATABASE
IF
IFNULL
ISNULL
LAST_INSERT_ID
NULLIF
SESSION_USER
SYSTEM_USER
USER
VERSION
SQL Server Functions
String Functions
ASCII
CHAR
CHARINDEX
CONCAT
Concat with +
CONCAT_WS
DATALENGTH
DIFFERENCE
FORMAT
LEFT
LEN
LOWER
LTRIM
NCHAR
PATINDEX
QUOTENAME
REPLACE
REPLICATE
REVERSE
RIGHT
RTRIM
SOUNDEX
SPACE
STR
STUFF
SUBSTRING
TRANSLATE
TRIM
UNICODE
UPPER
Numeric Functions
ABS
ACOS
ASIN
ATAN
ATN2
AVG
CEILING
COUNT
COS
COT
DEGREES
EXP
FLOOR
LOG
LOG10
MAX
MIN
PI
POWER
RADIANS
RAND
ROUND
SIGN
SIN
SQRT
SQUARE
SUM
TAN
Date Functions
CURRENT_TIMESTAMP
DATEADD
DATEDIFF
DATEFROMPARTS
DATENAME
DATEPART
DAY
GETDATE
GETUTCDATE
ISDATE
MONTH
SYSDATETIME
YEAR
Advanced Functions
CAST
COALESCE
CONVERT
CURRENT_USER
IIF
ISNULL
ISNUMERIC
NULLIF
SESSION_USER
SESSIONPROPERTY
SYSTEM_USER
USER_NAME
MS Access Functions
String Functions
Asc
Chr
Concat with &
CurDir
Format
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Format
Hour
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Second
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SQL OperatorsSQL Data TypesSQL Quick Ref
Introduction to MySQL TIMESTAMP data type
The MySQL is a temporal data type that holds the combination of date and time. The format of a is which is fixed at 19 characters.
The value has a range from to .
When you insert a value into a table, MySQL converts it from your connection’s time zone to UTC for storing.
When you query a value, MySQL converts the UTC value back to your connection’s time zone. Note that this conversion does not take place for other temporal data types such as .
By default, the connection time zone is the MySQL Server’s time zone. And you can use a different time zone when you connect to MySQL Server.
When you retrieve a value that was inserted by a client in a different time zone, you will get a value that is not the same as the value stored in the database. As long as you don’t change the time zone, you can get the same value that you stored.
MySQL time zone example
Let’s take an example to see how MySQL handles values.
First, created a new table named that has a column: ;
Second, set the session’s time zone to ‘+00:00’ UTC by using the statement.
Third, insert a value into the table.
Fourth, select the value from the table.
Fifth, set the session’s time zone to a different time zone to see what value we will get from the database server:
Finally, query data from the table:
As you see, we received a different time value adjusted to the new time zone.
MySQL DATETIME functions
The following statement sets the variable to the current date and time using the function.
To query the value of the variable, you use the following statement:
MySQL DATE function
To extract the date portion from a value, you use the function as follows:
This function is very useful in case you want to query data based on a date but the data stored in the column is based on both date and time.
Let’s see the following example.
Suppose you want to know which row created on , you use the following query:
It returns no rows.
This is because the column contains not only date but also time. To correct it, you use the function as follows:
It returns one row as expected. In case the table has many rows, MySQL has to perform a full table scan to locate the rows that match the condition.
To extract the time portion from a value, you use the function as the following statement:
MySQL YEAR, QUARTER, MONTH, WEEK, DAY, HOUR, MINUTE and SECOND functions
To get the year, quarter, month, week, day, hour, minute, and second from a value, you use the functions as shown in the following statement:
To format a value, you use the function. For example, the following statement formats a value based on the format:
To add an interval to a value, you use function as follows:
To subtract an interval from a value, you use function as follows:
MySQL DATE_DIFF function
To calculate a difference in days between two values, you use the function. Notice that the function only considers the date part of a value in the calculation.
See the following example.
First, create a table named that has one column whose data type is .
Second, insert some rows into the table.
Third, use the function to compare the current date and time with the value in each row of the table.
In this tutorial, you have learned about MySQL data type and some useful functions.
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SQL References
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ADD
ADD CONSTRAINT
ALTER
ALTER COLUMN
ALTER TABLE
ALL
AND
ANY
AS
ASC
BACKUP DATABASE
BETWEEN
CASE
CHECK
COLUMN
CONSTRAINT
CREATE
CREATE DATABASE
CREATE INDEX
CREATE OR REPLACE VIEW
CREATE TABLE
CREATE PROCEDURE
CREATE UNIQUE INDEX
CREATE VIEW
DATABASE
DEFAULT
DELETE
DESC
DISTINCT
DROP
DROP COLUMN
DROP CONSTRAINT
DROP DATABASE
DROP DEFAULT
DROP INDEX
DROP TABLE
DROP VIEW
EXEC
EXISTS
FOREIGN KEY
FROM
FULL OUTER JOIN
GROUP BY
HAVING
IN
INDEX
INNER JOIN
INSERT INTO
INSERT INTO SELECT
IS NULL
IS NOT NULL
JOIN
LEFT JOIN
LIKE
LIMIT
NOT
NOT NULL
OR
ORDER BY
OUTER JOIN
PRIMARY KEY
PROCEDURE
RIGHT JOIN
ROWNUM
SELECT
SELECT DISTINCT
SELECT INTO
SELECT TOP
SET
TABLE
TOP
TRUNCATE TABLE
UNION
UNION ALL
UNIQUE
UPDATE
VALUES
VIEW
WHERE
MySQL Functions
String Functions
ASCII
CHAR_LENGTH
CHARACTER_LENGTH
CONCAT
CONCAT_WS
FIELD
FIND_IN_SET
FORMAT
INSERT
INSTR
LCASE
LEFT
LENGTH
LOCATE
LOWER
LPAD
LTRIM
MID
POSITION
REPEAT
REPLACE
REVERSE
RIGHT
RPAD
RTRIM
SPACE
STRCMP
SUBSTR
SUBSTRING
SUBSTRING_INDEX
TRIM
UCASE
UPPER
Numeric Functions
ABS
ACOS
ASIN
ATAN
ATAN2
AVG
CEIL
CEILING
COS
COT
COUNT
DEGREES
DIV
EXP
FLOOR
GREATEST
LEAST
LN
LOG
LOG10
LOG2
MAX
MIN
MOD
PI
POW
POWER
RADIANS
RAND
ROUND
SIGN
SIN
SQRT
SUM
TAN
TRUNCATE
Date Functions
ADDDATE
ADDTIME
CURDATE
CURRENT_DATE
CURRENT_TIME
CURRENT_TIMESTAMP
CURTIME
DATE
DATEDIFF
DATE_ADD
DATE_FORMAT
DATE_SUB
DAY
DAYNAME
DAYOFMONTH
DAYOFWEEK
DAYOFYEAR
EXTRACT
FROM_DAYS
HOUR
LAST_DAY
LOCALTIME
LOCALTIMESTAMP
MAKEDATE
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MICROSECOND
MINUTE
MONTH
MONTHNAME
NOW
PERIOD_ADD
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QUARTER
SECOND
SEC_TO_TIME
STR_TO_DATE
SUBDATE
SUBTIME
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TIME
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Advanced Functions
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POWER
RADIANS
RAND
ROUND
SIGN
SIN
SQRT
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SUM
TAN
Date Functions
CURRENT_TIMESTAMP
DATEADD
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DATEPART
DAY
GETDATE
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MONTH
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YEAR
Advanced Functions
CAST
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Day
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SQL OperatorsSQL Data TypesSQL Quick Ref
Parameter Values
| Parameter | Description | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| date | Required. The date to be formatted | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| format | Required. The format to use. Can be one or a combination of the following values:
|
More Examples
Example
Add 5 seconds and 3 microseconds to a time and return the datetime:
SELECT ADDTIME(«2017-06-15
09:34:21.000001», «5.000003»);
Example
Add 2 hours, 10 minutes, 5 seconds, and 3 microseconds to a time and return the datetime:
SELECT ADDTIME(«2017-06-15 09:34:21.000001», «2:10:5.000003»);
Example
Add 5 days, 2 hours, 10 minutes, 5 seconds, and 3 microseconds to a time and return the datetime:
SELECT ADDTIME(«2017-06-15
09:34:21.000001», «5 2:10:5.000003»);
Example
Add 2 hours, 10 minutes, 5 seconds, and 3 microseconds to a time and return the time:
SELECT ADDTIME(«09:34:21.000001», «2:10:5.000003»);
MySQL DATETIME vs. TIMESTAMP
MySQL provides another temporal data type that is similar to the called .
The requires 4 bytes while requires 5 bytes. Both and require additional bytes for fractional seconds precision.
values range from to . If you want to store temporal values that are beyond 2038, you should use instead of .
MySQL stores in UTC value. However, MySQL stores the value as is without timezone. Let’s see the following example.
First, set the timezone of the current connection to .
Next, create a table named that consists of two columns: and with and types using the following statement.
Then, insert the current date and time into both and columns of the table,
After that, query data from the table.
Both values in and columns are the same.
Finally, set the connection’s time zone to and query data from the table again.
As you can see, the value in the column is different. This is because the column stores the date and time value in UTC when we changed the time zone, the value of the column is adjusted according to the new time zone.
It means that if you use the data to store date and time values, you should take a serious consideration when you move your database to a server located in a different time zone.
