feat: distinct param for count

Author: tpetry

README.md

@@ -202,7 +202,7 @@ use Tpetry\QueryExpressions\Function\Aggregate\{
 use Tpetry\QueryExpressions\Operator\Value\Value;
 
 new Avg(string|Expression $value);
-new Count(string|Expression $value);
+new Count(string|Expression $value, bool $distinct = false);
 new CountFilter(string|Expression $filter);
 new Max(string|Expression $value);
 new Min(string|Expression $value);

src/Function/Aggregate/Count.php

@@ -4,10 +4,27 @@
 
 namespace Tpetry\QueryExpressions\Function\Aggregate;
 
-class Count extends AggregateExpression
+use Illuminate\Contracts\Database\Query\Expression;
+use Illuminate\Database\Grammar;
+use Tpetry\QueryExpressions\Concerns\StringizeExpression;
+
+class Count implements Expression
 {
-    protected function aggregate(): string
+    use StringizeExpression;
+
+    public function __construct(
+        private readonly string|Expression $value,
+        private readonly bool $distinct = false,
+    ) {
+    }
+
+    public function getValue(Grammar $grammar): string
     {
-        return 'count';
+        $value = $this->stringize($grammar, $this->value);
+
+        return match ($this->distinct) {
+            true => "count(distinct {$value})",
+            false => "count({$value})",
+        };
     }
 }

tests/Function/Aggregate/CountTest.php

@@ -13,10 +13,26 @@
     ->toBeSqlite('count("val")')
     ->toBeSqlsrv('count([val])');
 
+it('can aggregate a column by COUNT with DISTINCT')
+    ->expect(new Count('val', true))
+    ->toBeExecutable(['val int'])
+    ->toBeMysql('count(distinct `val`)')
+    ->toBePgsql('count(distinct "val")')
+    ->toBeSqlite('count(distinct "val")')
+    ->toBeSqlsrv('count(distinct [val])');
+
 it('can aggregate an expression by COUNT')
     ->expect(new Count(new Expression(1)))
     ->toBeExecutable()
     ->toBeMysql('count(1)')
     ->toBePgsql('count(1)')
     ->toBeSqlite('count(1)')
     ->toBeSqlsrv('count(1)');
+
+it('can aggregate an expression by COUNT with DISTINCT')
+    ->expect(new Count(new Expression(1), true))
+    ->toBeExecutable()
+    ->toBeMysql('count(distinct 1)')
+    ->toBePgsql('count(distinct 1)')
+    ->toBeSqlite('count(distinct 1)')
+    ->toBeSqlsrv('count(distinct 1)');