问题描述
这里很直接的问题，我认为这应该有效，但它没有.为什么不呢?
Pretty straight forward question here, I think this should work but it doesn't. Why doesn't it?
CREATE TABLE INVOICE(
INVOICEDATE DATE NOT NULL DEFAULT CURRENT_DATE
)
推荐答案
它不起作用，因为它不受支持
It doesn't work because it's not supported
DEFAULT 子句指定列的默认值.除了一个例外，默认值必须是一个常量；它不能是函数或表达式.这意味着，例如，您不能将日期列的默认值设置为诸如 NOW() 或 CURRENT_DATE 之类的函数的值.例外是您可以将 CURRENT_TIMESTAMP 指定为 TIMESTAMP 列的默认值
The
DEFAULTclause specifies a default value for a column. With one exception, the default value must be a constant; it cannot be a function or an expression. This means, for example, that you cannot set the default for a date column to be the value of a function such asNOW()orCURRENT_DATE. The exception is that you can specifyCURRENT_TIMESTAMPas the default for aTIMESTAMPcolumn
http://dev.mysql.com/doc/refman/5.5/en/create-table.html
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