PHP MYSQL 更新如果存在或插入，如果不存在？

我都不知道这是不是真的。我有一个类，我想更新数据库，如果字段当前存在或插入，如果他们不存在。复杂的是，我正在做一个连接3个表(set _ color，school _ art，base image)

任何帮助都可以。

以下是我所知道的:

public function set_layer_colors($value) {
global $db;


$result_array = mysql_query("
IF EXISTS(SELECT * FROM set_colors WHERE school_art_id = '{$value}')


UPDATE set_colors (school_art_id, baseimage_id, sub_folder, layer)
SELECT school_art.id, baseimage.id, baseimage.sub_folder, baseimage.layer
FROM school_art
JOIN baseimage ON baseimage.base_folder = school_art.series_code
WHERE baseimage.image_type = 'B' ORDER BY school_art.id


ELSE


INSERT INTO set_colors (school_art_id, baseimage_id, sub_folder, layer)
SELECT school_art.id, baseimage.id, baseimage.sub_folder, baseimage.layer
FROM school_art
JOIN baseimage ON baseimage.base_folder = school_art.series_code
WHERE baseimage.image_type = 'B' ORDER BY school_art.id
");


return $result_array;
}