add if/if not exists to create table

src/Build/QueryBuilderTrait.php

@@ -306,4 +306,17 @@ public function checkQuery(string $column, array $expressions, array $checkSort
 
         return $result;
     }
+
+     /**
+     * build exists query
+     *
+     * @return string
+     */
+    public function exists():string
+    {
+        if(!$this->hasAttribute('exists')){
+            return '';
+        }
+        return $this->getAttribute('exists') ?  $this->syntax->getCommand('ifExists') :  $this->syntax->getCommand('ifNotExists'); 
+    }
 }

src/Build/TableQueryBuilder.php

@@ -249,8 +249,9 @@ public function tableCharset(): string
     public function buildCreateTable(): string
     {
         $query = sprintf(
-            "%s %s ( %s %s )  %s %s",
+            "%s %s %s ( %s %s )  %s %s",
             $this->start(),
+            $this->exists(),
             $this->tableName(),
             $this->columnQueryBuilder(),
             $this->check(),

src/Operations/CreateTable.php

@@ -60,19 +60,6 @@ public function charset(string $charset): self
         return $this;
     }
 
-    /**
-     * Specify whether the table should only be created if it does not already exist.
-     *
-     * @param bool $act Whether to create the table only if it doesn't exist.
-     *
-     * @return self
-     */
-    public function exists(bool $act = false): self
-    {
-        $this->setAttribute('exists', $act);
-        return $this;
-    }
-
     /**
      * Get the table constructs based on the provided table definition callback or configuration.
      *

src/Operations/OperationsTrait.php

@@ -312,5 +312,36 @@ public function whereTable(string $table)
         return $this;
     }
 
-
+    /**
+     * Specify whether the table should only be created if it does not already exist.
+     *
+     * @param bool $act Whether to create the table only if it doesn't exist.
+     *
+     * @return self
+     */
+    public function exists(bool $act = false): self
+    {
+        $this->setAttribute('exists', $act);
+        return $this;
+    }
+
+    /**
+     * Specify whether the table should only be created if exist.
+     *
+     * @return self
+     */
+    public function ifExists(): self
+    {
+        return $this->exists(true);
+    }
+
+    /**
+     * Specify whether the table should only be created if it does not already exist.
+     *
+     * @return self
+     */
+    public function ifNotExists(): self
+    {
+        return $this->exists(false);
+    }
 }