时间戳列的默认值无效

Question

我找不到为什么这在 MySQL 5.7 中无效（用 5.7.16 测试）

CREATE TABLE TEST_TABLE (ts TIMESTAMP DEFAULT CURRENT_TIMESTAMP);
INSERT INTO TEST_TABLE() VALUES ();
DROP TEMPORARY TABLE IF EXISTS TMP_TEST;
CREATE TEMPORARY TABLE TMP_TEST SELECT * FROM (SELECT ts FROM TEST_TABLE) wrap;

我得到这个：错误代码：1067。“ts”的默认值无效

是我遗漏了什么还是 mysql 的错误？

Answer 1

我无法重现该问题。

mysql> SELECT VERSION();
+-----------+
| VERSION() |
+-----------+
| 5.7.16    |
+-----------+
1 row in set (0,00 sec)

mysql> CREATE TABLE TEST_TABLE (ts TIMESTAMP DEFAULT CURRENT_TIMESTAMP);
Query OK, 0 rows affected (0,00 sec)

mysql> INSERT INTO TEST_TABLE() VALUES ();
Query OK, 1 row affected (0,00 sec)

mysql> SELECT * FROM (SELECT ts FROM TEST_TABLE) wrap;
+---------------------+
| ts                  |
+---------------------+
| 2016-11-04 00:00:01 |
+---------------------+
1 row in set (0,00 sec)

mysql> DROP TEMPORARY TABLE IF EXISTS TMP_TEST;
Query OK, 0 rows affected, 1 warning (0,00 sec)

mysql> CREATE TEMPORARY TABLE TMP_TEST;
ERROR 1113 (42000): A table must have at least 1 column

更新

更新问题后：

mysql> SELECT ts FROM TEST_TABLE;
Field   1:  `ts`
Catalog:    `def`
Database:   `test`
Table:      `TEST_TABLE`
Org_table:  `TEST_TABLE`
Type:       TIMESTAMP
Collation:  binary (63)
Length:     19
Max_length: 19
Decimals:   0
Flags:      NOT_NULL BINARY TIMESTAMP 

+---------------------+
| ts                  |
+---------------------+
| 2016-11-04 00:00:01 |
+---------------------+
1 row in set (0,00 sec)

mysql> SELECT * FROM (SELECT ts FROM TEST_TABLE) wrap;
Field   1:  `ts`
Catalog:    `def`
Database:   `test`
Table:      `wrap`
Org_table:  `*`
Type:       TIMESTAMP
Collation:  utf8_general_ci (33)
Length:     57
Max_length: 19
Decimals:   0
Flags:      NOT_NULL BINARY TIMESTAMP 

+---------------------+
| ts                  |
+---------------------+
| 2016-11-04 00:00:01 |
+---------------------+
1 row in set (0,00 sec)

注意排序规则的区别。

mysql> CREATE TEMPORARY TABLE TMP_TEST
    -> SELECT * FROM (SELECT BINARY ts FROM TEST_TABLE) wrap;
Query OK, 1 row affected (0,00 sec)
Records: 1  Duplicates: 0  Warnings: 0

更新 2

当查询尝试创建临时表时，子查询导致ts列的默认值被定义为'0000-00-00 00:00:00'并且服务器必须在变量SQL_MODE中配置NO_ZERO_DATE值，这会导致错误。

mysql> SELECT FIND_IN_SET('NO_ZERO_DATE', @@SQL_MODE);
+-----------------------------------------+
| FIND_IN_SET('NO_ZERO_DATE', @@SQL_MODE) |
+-----------------------------------------+
|                                       4 |
+-----------------------------------------+
1 row in set (0,00 sec)

从SQL_MODE 中删除NO_ZERO_DATE。

mysql> SELECT FIND_IN_SET('NO_ZERO_DATE', @@SQL_MODE);
+-----------------------------------------+
| FIND_IN_SET('NO_ZERO_DATE', @@SQL_MODE) |
+-----------------------------------------+
|                                       0 |
+-----------------------------------------+
1 row in set (0,00 sec)

mysql> DROP TEMPORARY TABLE IF EXISTS TMP_TEST;
Query OK, 0 rows affected (0,00 sec)

mysql> CREATE TEMPORARY TABLE TMP_TEST
    -> SELECT * FROM (SELECT ts FROM TEST_TABLE) wrap;
Query OK, 1 row affected (0,00 sec)
Records: 1  Duplicates: 0  Warnings: 0

mysql> SHOW CREATE TABLE TMP_TEST\G
*************************** 1. row ***************************
       Table: TMP_TEST
Create Table: CREATE TEMPORARY TABLE `TMP_TEST` (
  `ts` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00'
) ENGINE=InnoDB
1 row in set (0,00 sec)

您可以通过删除子查询来避免该问题。

mysql> SELECT FIND_IN_SET('NO_ZERO_DATE', @@SQL_MODE);
+-----------------------------------------+
| FIND_IN_SET('NO_ZERO_DATE', @@SQL_MODE) |
+-----------------------------------------+
|                                       4 |
+-----------------------------------------+
1 row in set (0,00 sec)

mysql> DROP TEMPORARY TABLE IF EXISTS TMP_TEST;
Query OK, 0 rows affected (0,00 sec)

mysql> CREATE TEMPORARY TABLE TMP_TEST
    -> SELECT ts FROM TEST_TABLE;
Query OK, 1 row affected (0,00 sec)
Records: 1  Duplicates: 0  Warnings: 0

mysql> SHOW CREATE TABLE TMP_TEST\G
*************************** 1. row ***************************
       Table: TMP_TEST
Create Table: CREATE TEMPORARY TABLE `TMP_TEST` (
  `ts` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP
) ENGINE=InnoDB
1 row in set (0,00 sec)