2009-08-24 258 views
0

我在看一些練習題,MySQL的時間戳問題

Assume that you've just created this table: 


CREATE TABLE timestamptest (
ts1 TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP, 
i INT 
); 


When you look at its structure, you will notice that the TIMESTAMP column is declared NOT NULL. What happens if you insert these records: 

mysql> INSERT INTO timestamptest SET ts1=NULL, i=10; 
mysql> INSERT INTO timestamptest SET ts1=0, i=11; 
mysql> INSERT INTO timestamptest SET ts1='', i=12; 

俺們是

Only the first statement succeeds, and the TIMESTAMP column is set to the current date and time. The other two statements give an error: 

mysql> INSERT INTO timestamptest SET ts1=NULL, i=10; 
Query OK, 1 row affected (0.00 sec) 

mysql> INSERT INTO timestamptest SET ts1=0, i=11; 
ERROR 1292 (22007): Incorrect datetime value: '0' for column 'ts1' at row 1 
mysql> INSERT INTO timestamptest SET ts1='', i=12; 
ERROR 1292 (22007): Incorrect datetime value: '' for column 'ts1' at row 1 

但是當我試圖,將TS1 = 0的作品,它插入一個零值時間戳...答案錯了嗎?

回答

4

這取決於NO_ZERO_DATE選項是否設置:

mysql> create table foo(x timestamp); 
Query OK, 0 rows affected (0.01 sec) 

mysql> set sql_mode=''; 
Query OK, 0 rows affected (0.00 sec) 

mysql> insert into foo values(0); 
Query OK, 1 row affected (0.00 sec) 

mysql> set sql_mode='strict_all_tables,no_zero_date'; 
Query OK, 0 rows affected (0.00 sec) 

mysql> insert into foo values(0); 
ERROR 1292 (22007): Incorrect datetime value: '0' for column 'x' at row 1