[bugfix/max_and_min_string]

[tt88dev]

Bugfix feature - String columns to support MAX and MIN

We have the following table:

class example extends Table {
  IntColumn get id => integer().autoIncrement()();
  TextColumn get name => text()();
  TextColumn get string_type => text().withDefault(const Constant('N'))(); //N,Y
  RealColumn get quantity => real()();
}

Example Table:

id	name	string_type	quantity
1	TREE01	N	700.0
2	TREE01	N	800.0
3	TREE01	N	600.0
4	TREE01	Y	200.0

We need to execute the following SQL:

SELECT
	"example"."name" AS "example.name",
	MAX("example"."string_type") AS "c1",
	SUM("example"."quantity") AS "c2"
FROM
	"example"
GROUP BY
	"example"."name"

Result:

example.name	c1	c2
TREE01	Y	2300.0

The following is how to use it.

    final maxStringType = example.string_type.max(); //<-- Fix this LINE
    final sumQuantity = example.quantity.sum();
    final queryExample = selectOnly(
      example,
    )
      ..addColumns([
        example.name,
        maxStringType,
        sumQuantity,
      ])
      ..groupBy([
        example.name,
      ])
     ;

[simolus3]

Thanks for the contribution!

Could you add a test for this as well? test/database/expressions/aggregate_test.dart has the others, you can test this for strings in a similar way by creating a CustomExpression<String>

[tt88dev]

Thanks for the contribution!

Could you add a test for this as well? test/database/expressions/aggregate_test.dart has the others, you can test this for strings in a similar way by creating a CustomExpression<String>

Certainly! I've already added a test for that along with the recent changes.

[tt88dev]

Thanks for the contribution!
Could you add a test for this as well? test/database/expressions/aggregate_test.dart has the others, you can test this for strings in a similar way by creating a CustomExpression<String>

Certainly! I've already added a test for that along with the recent changes.

In addition, I have just helped to complete more other tests, in another Issue, please refer to #2819

[simolus3]

Looks great, thanks!