FunctionalQueryField

An extended query field class for defining functional SQL expressions. Useful for applying SQL functions to query conditions. Inherits QueryField.

Usability

The following example applies the TRIM function to a column condition.

var where = new FunctionalQueryField("Column", "Value", "TRIM({0})");
var result = connection.Query<Entity>(where);

The result contains all records where the trimmed value of Column equals Value.

GetString

The GetString() method returns the SQL command text with the specified function applied.

var where = new FunctionalQueryField("Column", "Value", "TRIM({0})");
var text = where.GetString(connection.GetDbSetting()); // Returns (TRIM([Column]) = @Column)

Formatting

The library uses string.Format() to compose the expression. In the format argument, use {0} as the placeholder for the field name.

var where = new FunctionalQueryField("Column", "Value", "LEN({0}) > 5 AND RIGHT({0})");
var text = where.GetString(connection.GetDbSetting()); // Returns (LEN([Column]) > 5 AND RIGHT([Column]) = @Column)