Partager via

Literals

  • Article

A literal is a string of characters that represents a value in a query statement. You use literals to compare column values or to specify search terms. Windows Search supports the following types of literals.

  • String literals are not limited in length and can contain either ANSI or Unicode characters. You must enclose string literals in single quotation marks. To include a single quotation mark inside a string literal, use two single quotation marks. Represent an empty string as two consecutive single quotation marks ('').
  • Numeric literals can contain the digits 0-9, a period, and the letter E (or e). Numeric literals represent numbers, including positive and negative integers, decimal numbers, and currency values. Numeric literals can be defined by using scientific notation (for example, 2.3E-05). Do not enclose a numeric literal in single quotation marks, or it will be interpreted as a string literal and compared using string comparison techniques. Currency values cannot contain currency symbols.
  • Hexadecimal literals can contain the digits 0-9 and the letters A-F and a-f. A hexadecimal literal represents an unsigned integer specified in hexadecimal notation. Hexadecimal literals must begin with 0x. Note  The SQL-92 standard requires that hexadecimal literals be enclosed in single quotation marks; however, Windows Search does not support that notation.
  • Boolean literals represent logical values, and can be either TRUE or FALSE. Do not enclose a Boolean literal in single quotation marks, or it is interpreted as a string literal.
  • Date literals represent specific dates, time stamps, or relative times, and are enclosed in single quotation marks. You must put dates in the form year/month/day or year-month-day, where the month, day, and year are numbers. Specify the year with a four-digit value, for example, 2004. Time values must be in the form hours:minutes:seconds. Relative time syntax is based on the DATEADD function.