Syntax rules for search filters

  1. The first line contains always the text <select where>. This formulation was based on SQL.
  2. The second line always begins with a left parenthesis.
  3. The further lines contain a filter instruction or a parenthesis.
  4. The last line contains the right parenthesis.

Logical operators for filter instructions

AND: The filter instruction of this line is AND combined with the preceding one.

OR: The filter instruction of this line is OR combined with the preceding one.


Compare operators <, >, =, <> and compare values

Upper-case / lower-case are ignored!
<, > Number: Numeric compare of field contents and number.
<, > íTextí: Text compare of field contents and number.
= Number: Test if equal. (Numeric compare)
= íTextí: Test if equal. (Text compare)
= í*Textí: Test whether the field content contains 'text'.
= íText*í: Test whether the field content begins with 'text'.
<> íTextí: Test whether the field contents is different from 'text'.
<> Number: Test whether the field content is different from Number.


Filter Instruction (line)

Example with two lines

<font face="Courier New">select where
(
    City = 'Berlin'
    AND Firm = '*Inc'
) )

  • The first filter instruction to a left parenthesis begins with a field name. All further filter instructions within the same parenthesis level begin with a logical operator (AND/OR), followed from a field name.
  • After the field name comes a blank, then a compare operator, then again a blank followed from the compare value.

Example with sub-parenthesis

<font face="Courier New">select where
(
    City = 'Berlin'
    AND (
            Firm = '*Inc'
            OR Firm = '* AG.'
        )
) )

  • Subordinate clip tiers can be inserted by hand. You always begin with a logical operator (AND/OR), followed from a left parenthesis and a line wrap. (Behind a left parenthesis no further instructions must stand in the same line.)
  • The following lines contain in each case a filter instruction.
  • The left parenthesis is to be locked through a left parenthesis in a separate line.
  • In order to increase the readability, the clip tiers should be indented as in the example. Blanks or tabulators can be used for that.