APIv4 - Automatically coalesce potentially null field values in equations

Civi/Api4/Query/SqlEquation.php

@@ -70,7 +70,17 @@ protected function initialize() {
   public function render(array $fieldList): string {
     $output = [];
     foreach ($this->args as $arg) {
-      $output[] = is_string($arg) ? $arg : $arg->render($fieldList);
+      // Just an operator
+      if (is_string($arg)) {
+        $output[] = $arg;
+      }
+      // Surround fields with COALESCE to handle null values
+      elseif (is_a($arg, SqlField::class)) {
+        $output[] = 'COALESCE(' . $arg->render($fieldList) . ', 0)';
+      }
+      else {
+        $output[] = $arg->render($fieldList);
+      }
     }
     return '(' . implode(' ', $output) . ')';
   }

tests/phpunit/api/v4/Action/SqlExpressionTest.php

@@ -108,7 +108,10 @@ public function testSelectEquations() {
         '(5 > 11) AS five_greater_eleven',
         '(5 <= 11) AS five_less_eleven',
         '(1 BETWEEN 0 AND contact_id) AS is_between',
+        // These fields don't exist
         '(illegal * stuff) AS illegal_stuff',
+        // This field will be null
+        '(hold_date + 5) AS null_plus_five',
       ])
       ->addWhere('contact_id', '=', $contact['id'])
       ->setLimit(1)
@@ -121,6 +124,7 @@ public function testSelectEquations() {
     $this->assertTrue($result['five_less_eleven']);
     $this->assertTrue($result['is_between']);
     $this->assertArrayNotHasKey('illegal_stuff', $result);
+    $this->assertEquals('5', $result['null_plus_five']);
   }
 
 }