我對下面的查詢有一些問題,我不確定如何修改它以給我所需的輸出,詳情如下：
select listup.nodenumber as node, listup.station as extension,
case when voiceserver = 1 then keydescription else '' end as 'key1',
case when voiceserver = 2 then keydescription else '' end as 'key2',
case when voiceserver = 3 then keydescription else '' end as 'key3',
case when voiceserver = 4 then keydescription else '' end as 'key4',
case when voiceserver = 5 then keydescription else '' end as 'key5',
case when voiceserver = 6 then keydescription else '' end as 'key6',
case when voiceserver = 7 then keydescription else '' end as 'key7',
case when voiceserver = 8 then keydescription else '' end as 'key8',
case when voiceserver = 9 then keydescription else '' end as 'key9',
case when voiceserver = 10 then keydescription else '' end as 'key10'
from listup
order by listup.nodenumber, listup.station;
輸出如下：
node extension key1 key2 key3 etc.
n100 14311 14311
n100 14311 14308
n100 14311 14309
n100 14311 14314
n100 14311 14412
n100 14311 14535
n100 14311 14316
n100 14311 14456
n100 14312 14312
n100 14312 14442
n100 14312 14311
n100 14312 14314
n100 14312 14456
n100 14312 14309
n100 14312 14308
我想把它全部出現在一條線上,所以這樣扁平化了……
例如.n100 14311 14311 14308 14309 14314 14412 14535 14316 14456
n100 14312 14312 14442 14311 14314 14456 14309 14308
解決方法:
您需要定義group by子句,並使用max聚合來獲取所需的輸出：
select listup.nodenumber as node, listup.station as extension,
max(case when voiceserver = 1 then keydescription else null end) as 'key1',
max(case when voiceserver = 2 then keydescription else null end) as 'key2',
max(case when voiceserver = 3 then keydescription else null end) as 'key3',
max(case when voiceserver = 4 then keydescription else null end) as 'key4',
max(case when voiceserver = 5 then keydescription else null end) as 'key5',
max(case when voiceserver = 6 then keydescription else null end) as 'key6',
max(case when voiceserver = 7 then keydescription else null end) as 'key7',
max(case when voiceserver = 8 then keydescription else null end) as 'key8',
max(case when voiceserver = 9 then keydescription else null end) as 'key9',
max(case when voiceserver = 10 then keydescription else null end) as 'key10'
from listup
group by listup.nodenumber as node, listup.station as extension
order by listup.nodenumber, listup.station
null優於零長度字串.
標籤：mysql,sql,pivot
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