| Operation | Description |
|---|---|
|
column_name "column_name" |
value of field column_name |
| 'string' | literal string value |
| number | number |
| NULL | null value |
| sqrt(a) | square root |
| sin(a) | sinus of a |
| cos(a) | cosinus of b |
| tan(a) | tangens of a |
| asin(a) | arcussinus of a |
| acos(a) | arcuscosinus of a |
| atan(a) | arcustangens of a |
| to int(a) | convert string a to integer |
| to real(a) | convert string a to real |
| to string(a) | convert number a to string |
| lower(a) | convert string a to lower case |
| upper(a) | convert string a to upper case |
| length(a) | length of string a |
| atan2(y,x) | arcustangens of y/x using the signs of the two arguments to determine the quadrant of the result. |
| replace(a,replacethis,withthat) | replace replacethis with withthat in string a |
| substr(a,from,len) | len characters of string a starting from from (first character index is 1) |
| a || b | concatenate strings a and b |
| $rownum | number current row |
| $area | area of polygon |
| $perimeter | perimeter of polygon |
| $length | area of line |
| $id | feature id |
| $x | x coordinate of point |
| $y | y coordinate of point |
| a ^ b | a raised to the power of b |
| a * b | a multiplied by b |
| a / b | a divided by b |
| a + b | a plus b |
| a - b | a minus b |
| +a | positive sign |
| -a | negative value of a |