If you omit a table name (that is, you specify NULL or an empty string), information is returned for all tables in the schema specified.

如果您省略了表名(即指定NULL或空字符串)，那么为指定的模式中的所有表返回信息。

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This expression also removes all null characters and excess whitespace.

此表达式也会删除所有空字符和过量的空白。

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A null return value implies all active slices, while an empty array will raise an exception.

空返回值意味着所有片都是活动的，而空数组则会引发一个异常。

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He and his best friend, Brad Null, hit the road after graduating from Stanford in 1998 to catch home games at all 30 big-league parks.

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