首页select count(0) from

select count(0) from

时间: 2023-05-02 13:01:13 浏览: 133

文字literal字符串-SELECT语句

文字（literal）字符串文字字符串是包含在一个Select语句中的字符串、数字、或者日期。文字字符串必须用单引号（‘’）括起来。对于返回的每一行，文字字符串都显示一次。在生成报表时非常有用。 Literal Character Strings A literal is character, a number, or a date included in the SELECT list that is not a column name or a column alias. It is printed for each row returned. Literal strings of free-format text can be included in the query result and are treated the same as a column in the SELECT list. Date and character literals must be enclosed within single quotation marks (' '); number literals must not.

这是一条 SQL 查询语句，意思是查询某个表中记录的数量。其中的 count 函数用于统计记录数。具体使用方法为：在括号中填写需要统计的字段，若用 0 则表示全部字段。例如，select count(*) from table 是查询 table 表中所有记录的数量。

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