文件名称：文字literal字符串-SQL语言基础
文件大小：5.26MB
文件格式：PPT
更新时间：2024-05-15 13:24:48
SQL 基础
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.