diff --git a/.github/workflows/active-record.yml b/.github/workflows/active-record.yml
index 6f7b9cb78..a894fad8a 100644
--- a/.github/workflows/active-record.yml
+++ b/.github/workflows/active-record.yml
@@ -26,7 +26,7 @@ jobs:
     name: PHP ${{ matrix.php }}-active-record-${{ matrix.os }}
 
     env:
-      COMPOSER_ROOT_VERSION: 1.1.0
+      COMPOSER_ROOT_VERSION: 1.2.0
       EXTENSIONS: pdo, pdo_mysql, pdo_oci, pdo_pgsql, pdo_sqlite, pdo_sqlsrv-5.10.1
 
     runs-on: ${{ matrix.os }}
diff --git a/.github/workflows/db-mariadb.yml b/.github/workflows/db-mariadb.yml
index 1ecc6bc67..7f69f4074 100644
--- a/.github/workflows/db-mariadb.yml
+++ b/.github/workflows/db-mariadb.yml
@@ -26,7 +26,7 @@ jobs:
     name: PHP ${{ matrix.php }}-mariadb-${{ matrix.mariadb }}
 
     env:
-      COMPOSER_ROOT_VERSION: 1.0.0
+      COMPOSER_ROOT_VERSION: 1.2.0
       CURRENT_PACKAGE: db-mysql
       EXTENSIONS: pdo, pdo_mysql
 
diff --git a/.github/workflows/db-mssql.yml b/.github/workflows/db-mssql.yml
index a3000c876..8fab1e591 100644
--- a/.github/workflows/db-mssql.yml
+++ b/.github/workflows/db-mssql.yml
@@ -26,7 +26,7 @@ jobs:
     name: PHP ${{ matrix.php }}-mssql-${{ matrix.mssql }}
 
     env:
-      COMPOSER_ROOT_VERSION: 1.0.0
+      COMPOSER_ROOT_VERSION: 1.2.0
       CURRENT_PACKAGE: db-mssql
       EXTENSIONS: pdo, pdo_sqlsrv-5.10.1
 
diff --git a/.github/workflows/db-mysql.yml b/.github/workflows/db-mysql.yml
index 6e6b51baa..a56b3f2fb 100644
--- a/.github/workflows/db-mysql.yml
+++ b/.github/workflows/db-mysql.yml
@@ -26,7 +26,7 @@ jobs:
     name: PHP ${{ matrix.php }}-mysql-${{ matrix.mysql }}
 
     env:
-      COMPOSER_ROOT_VERSION: 1.0.0
+      COMPOSER_ROOT_VERSION: 1.2.0
       CURRENT_PACKAGE: db-mysql
       EXTENSIONS: pdo, pdo_mysql
 
diff --git a/.github/workflows/db-oracle.yml b/.github/workflows/db-oracle.yml
index 75cdc548e..a37592db0 100644
--- a/.github/workflows/db-oracle.yml
+++ b/.github/workflows/db-oracle.yml
@@ -27,7 +27,7 @@ jobs:
 
     env:
       CURRENT_PACKAGE: db-oracle
-      COMPOSER_ROOT_VERSION: 1.0.0
+      COMPOSER_ROOT_VERSION: 1.2.0
       EXTENSIONS: pdo, pdo_oci
 
     runs-on: ${{ matrix.os }}
diff --git a/.github/workflows/db-pgsql.yml b/.github/workflows/db-pgsql.yml
index d2db8a700..0a809bdda 100644
--- a/.github/workflows/db-pgsql.yml
+++ b/.github/workflows/db-pgsql.yml
@@ -26,7 +26,7 @@ jobs:
     name: PHP ${{ matrix.php }}-pgsql-${{ matrix.pgsql }}
 
     env:
-      COMPOSER_ROOT_VERSION: 1.0.0
+      COMPOSER_ROOT_VERSION: 1.2.0
       CURRENT_PACKAGE: db-pgsql
       EXTENSIONS: pdo, pdo_pgsql
 
diff --git a/.github/workflows/db-sqlite.yml b/.github/workflows/db-sqlite.yml
index cf7c014a6..230ee0989 100644
--- a/.github/workflows/db-sqlite.yml
+++ b/.github/workflows/db-sqlite.yml
@@ -26,7 +26,7 @@ jobs:
     name: PHP ${{ matrix.php }}-sqlite-${{ matrix.os }}
 
     env:
-      COMPOSER_ROOT_VERSION: 1.0.0
+      COMPOSER_ROOT_VERSION: 1.2.0
       CURRENT_PACKAGE: db-sqlite
       EXTENSIONS: pdo, pdo_sqlite
 
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 293e1f8df..44d5f549f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,7 +2,8 @@
 
 ## 1.2.1 under development
 
-- no changes in this release.
+- Bug #777: Fix `Query::count()` when it returns an incorrect value if the result is greater
+  than `PHP_INT_MAX` (@Tigrov)
 
 ## 1.2.0 November 12, 2023
 
diff --git a/src/Query/Query.php b/src/Query/Query.php
index 98e69b962..8aa9cc517 100644
--- a/src/Query/Query.php
+++ b/src/Query/Query.php
@@ -293,10 +293,14 @@ public function column(): array
 
     public function count(string $sql = '*'): int|string
     {
-        return match ($this->emulateExecution) {
-            true => 0,
-            false => is_numeric($count = $this->queryScalar("COUNT($sql)")) ? (int) $count : 0,
-        };
+        /** @var int|string|null $count */
+        $count = $this->queryScalar("COUNT($sql)");
+
+        if ($count === null) {
+            return 0;
+        }
+
+        return $count <= PHP_INT_MAX ? (int) $count : $count;
     }
 
     public function createCommand(): CommandInterface
diff --git a/tests/AbstractQueryTest.php b/tests/AbstractQueryTest.php
index 63334ea9a..754cab5a3 100644
--- a/tests/AbstractQueryTest.php
+++ b/tests/AbstractQueryTest.php
@@ -787,4 +787,18 @@ public function testNormalizeSelect(array|string|Expression $columns, array|stri
         $query->select($columns);
         $this->assertEquals($expected, $query->getSelect());
     }
+
+    public function testCountGreaterThanPhpIntMax(): void
+    {
+        $query = $this->getMockBuilder(Query::class)
+            ->setConstructorArgs([$this->getConnection()])
+            ->onlyMethods(['queryScalar'])
+            ->getMock();
+
+        $query->expects($this->once())
+            ->method('queryScalar')
+            ->willReturn('12345678901234567890');
+
+        $this->assertSame('12345678901234567890', $query->count());
+    }
 }