Php 我如何让组_CONCAT返回一行以上的查询？

以上是我的数据。 这是我的问题

TXNID PARENT_TXN_ID ITEM_NAME
5G161631H9141883L Merchandise Total 4HD251984H4919123 Woodworking 101@Fri 04-05-2013 8:00 pm 4LA48638GR031562M Woodworking 101@Fri 04-05-2013 8:00 pm 6TU64611FM249252D Woodworking 101@Fri 04-05-2013 8:00 pm 7S953179AV7967542 Woodworking 101@Fri 04-05-2013 8:00 pm 04916720G2800071A Woodworking 101@Fri 04-05-2013 8:00 pm test1 4HD251984H4919123 setet 这只返回1行…我想它应该返回5行。我只是不确定为什么只返回一行。

请尝试使用group by

您没有分组依据，因此分组仅将每个结果行分组在一起。

SELECT ppv1.*,GROUP_CONCAT(ppv2.txn_id SEPARATOR ' <BR>') GC 
from paypal_valid ppv1
LEFT JOIN (SELECT txn_id,parent_txn_id from paypal_valid where parent_txn_id!='')
ppv2 ON ppv1.txn_id=ppv2.parent_txn_id
where ppv1.item_name!='Merchandise Total' and ppv1.parent_txn_id=''

 SELECT ppv1.*,GROUP_CONCAT(ppv2.txn_id SEPARATOR ' <BR>') GC 
 from paypal_valid ppv1
LEFT JOIN (SELECT txn_id,parent_txn_id from paypal_valid where parent_txn_id!='')
 ppv2 ON ppv1.txn_id=ppv2.parent_txn_id
where ppv1.item_name!='Merchandise Total' and ppv1.parent_txn_id=''
group by ppv1.txn_id
                ^^^-------//make sure u have this in your ppv1 table