mySQLの日付処理いろいろ

mySQLでよく使う日付処理をまとめてみました。
もっと良い書き方があれば、コメントをお願いします。

• システム日付

mysql> select curdate();
+------------+
| curdate() |
+------------+
| 2016-02-26 |
+------------+
1 row in set (0.16 sec)

mysql> select curdate() + 0;
+---------------+
| curdate() + 0 |
+---------------+
| 20160226 |
+---------------+
1 row in set (0.00 sec)

• システム日付時刻

mysql> select now();
+---------------------+
| now() |
+---------------------+
| 2016-02-26 12:16:15 |
+---------------------+
1 row in set (0.00 sec)

mysql> select now()+0;
+-----------------------+
| now()+0 |
+-----------------------+
| 20160226121618.000000 |
+-----------------------+
1 row in set (0.00 sec)

• 当月1日

mysql> select DATE_FORMAT( CURDATE() , '%Y-%m-01' );
+---------------------------------------+
| DATE_FORMAT( CURDATE() , '%Y-%m-01' ) |
+---------------------------------------+
| 2016-02-01 |
+---------------------------------------+
1 row in set (0.00 sec)

• 当月末日

mysql> select AST_DAY(CURDATE());
+---------------------+
| LAST_DAY(CURDATE()) |
+---------------------+
| 2016-02-29 |
+---------------------+
1 row in set (0.00 sec)

• 前月1日

mysql> select DATE_FORMAT( ADDDATE( CURDATE() , INTERVAL -1 MONTH) , '%Y-%m-01' );
+---------------------------------------------------------------------+
| DATE_FORMAT( ADDDATE( CURDATE() , INTERVAL -1 MONTH) , '%Y-%m-01' ) |
+---------------------------------------------------------------------+
| 2016-01-01 |
+---------------------------------------------------------------------+
1 row in set (0.00 sec)

• 前月末日

mysql> select LAST_DAY( ADDDATE( CURDATE() , INTERVAL -1 MONTH) );
+-----------------------------------------------------+
| LAST_DAY( ADDDATE( CURDATE() , INTERVAL -1 MONTH) ) |
+-----------------------------------------------------+
| 2016-01-31 |
+-----------------------------------------------------+
1 row in set (0.00 sec)

• 来月1日

mysql> select DATE_FORMAT( ADDDATE( CURDATE() , INTERVAL 1 MONTH) , '%Y-%m-01' );
+--------------------------------------------------------------------+
| DATE_FORMAT( ADDDATE( CURDATE() , INTERVAL 1 MONTH) , '%Y-%m-01' ) |
+--------------------------------------------------------------------+
| 2016-03-01 |
+--------------------------------------------------------------------+
1 row in set (0.00 sec)

• 来月末日

mysql> select LAST_DAY( ADDDATE( CURDATE() , INTERVAL 1 MONTH) );
+----------------------------------------------------+
| LAST_DAY( ADDDATE( CURDATE() , INTERVAL 1 MONTH) ) |
+----------------------------------------------------+
| 2016-03-31 |
+----------------------------------------------------+
1 row in set (0.00 sec)

• 当日分（1日分） (column_nameはdatetime)

select count(*) from table_name where date(column_name) = curdate();

• 当月分（1か月分） (column_nameはdatetime)

select count(*) from table_name where column_name >= DATE_FORMAT( CURDATE() , '%Y-%m-01' ) and column_name <= LAST_DAY(CURDATE());