private static string ResolveExpression(this IContext c, Filter filter) {
if (!string.IsNullOrEmpty(filter.Expression))
return filter.Expression;
var builder = new StringBuilder();
var rightSide = ResolveSide(filter, "right");
var resolvedOperator = ResolveOperator(filter.Operator);
if (rightSide.Equals("NULL")) {
if (filter.Operator == "=") {
resolvedOperator = "IS";
}
if (filter.Operator == "!=") {
resolvedOperator = "IS NOT";
}
}
builder.Append(ResolveSide(filter, "left"));
builder.Append(" ");
builder.Append(resolvedOperator);
builder.Append(" ");
builder.Append(rightSide);
var expression = builder.ToString();
c.Info("Filter: {0}", expression);
return expression;
}
private static string ResolveSide(Filter filter, string side) {
bool isField;
string value;
bool otherIsField;
Field otherField;
if (side == "left") {
isField = filter.LeftIsField;
value = filter.Left;
otherIsField = filter.RightIsField;
otherField = filter.RightField;
} else {
isField = filter.RightIsField;
value = filter.Right;
otherIsField = filter.LeftIsField;
otherField = filter.LeftField;
}
if (isField)
return SqlConstants.L + value + SqlConstants.R;
if (value.Equals("null", StringComparison.OrdinalIgnoreCase))
return "NULL";
if (!otherIsField) {
double number;
if (double.TryParse(value, out number)) {
return number.ToString(CultureInfo.InvariantCulture);
}
return SqlConstants.T + value + SqlConstants.T;
}
if (SqlConstants.StringTypes.Any(st => st == otherField.Type)) {
return SqlConstants.T + value + SqlConstants.T;
}
return value;
}
