如果不存在并从数据库中获取正确的值

Question

I am trying to insert list of items from dev.test1 table, but I am struggling with logic ...

Face following problems:

• Before insert statements I would like to add "if not exists" - select content in dev.qa_postmetas
• f.URL which I am getting in second query is not coming from correct row in dev.test1 - If want to select f.URL where f.title = b.title

Query:

INSERT INTO dev.qa_posts (type, categoryid, userid, created, title, content,          tags)
(SELECT  'Q_QUEUED', '1', '3', NOW(), f.title, f.img, f.tagsv
FROM dev.test1 f)
LIMIT 1;

INSERT INTO dev.qa_postmetas (postid, title, content) 
(select MAX(b.postid) , 'qa_q_extra',f.URL
from dev.qa_posts b
left JOIN dev.test1 as f on b.postid = f.id)
LIMIT 1 ;

Any assistance will be appreciated

Answer 1

To avoid emty records try IS NULL function in MySQL.

Second query you join to another one and limiting insertion to one. You may have more results from joined query then you attemt to insert.

Debug your second join select to check what results you have. Take out limitation to insert all records from joined queries.

Is that what you mean?