mysql连接表限制特定表

Question

I've created this SQL query in order to connect key variables and extract info from a database.

Firstly I used this:

SELECT * 
FROM `users` a,`field_data_field_ypefthinos` b, `field_data_field_branch_chain` c, `field_data_field_taxonomy_etairia` d, `node_revision` e
WHERE a.uid = b.field_ypefthinos_uid
AND a.uid = 1
AND b.entity_id = c.entity_id
AND d.field_taxonomy_etairia_tid = c.field_branch_chain_tid
AND d.bundle = 'kouponia'
AND d.entity_id = e.nid

and then I converted it to this in order to be able to use stmt bind_result function

SELECT
users.uid, 
field_data_field_ypefthinos.field_ypefthinos_uid, 
field_data_field_ypefthinos.entity_id,
field_data_field_branch_chain.entity_id,
field_data_field_taxonomy_etairia.field_taxonomy_etairia_tid,
field_data_field_taxonomy_etairia.bundle,
field_data_field_taxonomy_etairia.entity_id,
node_revision.nid
FROM `users`,`field_data_field_ypefthinos`, `field_data_field_branch_chain`, `field_data_field_taxonomy_etairia`, `node_revision`
WHERE users.uid = field_data_field_ypefthinos.field_ypefthinos_uid
AND users.uid = 1
AND field_data_field_ypefthinos.entity_id = field_data_field_branch_chain.entity_id
AND field_data_field_taxonomy_etairia.field_taxonomy_etairia_tid = field_data_field_branch_chain.field_branch_chain_tid
AND field_data_field_taxonomy_etairia.bundle = 'kouponia'
AND field_data_field_taxonomy_etairia.entity_id = node_revision.nid

What I'd like to do next is to:

1) use table/fields aliases in order for the code to be easier maintained as I do in the first code.

2) Important: be able to limit the results from table field_data_field_ypefthinos to LIMIT 1.

My goal is to have a code like this:

SELECT a.uid, b.field_ypefthinos_uid, b.entity_id, c.entity_id, d.field_taxonomy_etairia_tid, c.field_branch_chain_tid, d.bundle, d.entity_id
FROM `users` a,`field_data_field_ypefthinos` b LIMIT 1, `field_data_field_branch_chain` c, `field_data_field_taxonomy_etairia` d, `node_revision` e
WHERE a.uid = b.field_ypefthinos_uid
AND a.uid = 1
AND b.entity_id = c.entity_id
AND d.field_taxonomy_etairia_tid = c.field_branch_chain_tid
AND d.bundle = 'kouponia'
AND d.entity_id = e.nid

Answer 1

DISTINCT did the job, the solution:

SELECT DISTINCT e.title
FROM `users` a,`field_data_field_ypefthinos` b, `field_data_field_branch_chain` c, `field_data_field_taxonomy_etairia` d, `node_revision` e
WHERE a.uid = b.field_ypefthinos_uid
AND a.uid = 1
AND b.entity_id = c.entity_id
AND d.field_taxonomy_etairia_tid = c.field_branch_chain_tid
AND d.bundle = 'kouponia'
AND d.entity_id = e.nid