Question

I’m developing an Android 3.1 Tablet application which uses SQLite 3.

I have these three tables:

| Articles    |
+-------------+
| articleId   |
+-------------+
| description |
+-------------+


| OrdeArticle |
+-------------+
| orderId     |
+-------------+
| articleId   |
+-------------+


| EReportArticle |
+----------------+
| eReportId      |
+----------------+
| articleId      |
+----------------+

I want to select all articles which are on OrdeArticle table but they aren’t on EReportArticle table.

Here is my not working SQL sentence:

SELECT 
   Article.articleId,
   Article.description
FROM
   Article,
   OrdeArticle,
   EReportArticle
WHERE
   OrdeArticle.orderId = ? AND 
   Article.articleId = OrdeArticle.articleId AND
   EReportArticle.eReportId = ? AND
   Article.articleId != EReportArticle.articleId;

What am I doing wrong?

Answer 1

Try using IN statement to check if articleId exists in one table and doesn’t in another

SELECT articleId, description
FROM Articles
WHERE articleId IN (SELECT articleId FROM OrdeArticle) AND
articleId NOT IN (SELECT articleId FROM EReportArticle)