[英]What SELECT statement will get the non-zero values from table rows?
如果我在27列的表中有多行,這些都是這樣的整數
id_1 id_2 id_3 id_4 id_5 id_6 id_7 id_8 id_9 id_10 id_11 id_12 id_13 id_14 id_15 id_16 id_17 id_18 id_19 id_20 id_21 id_22 id_23 id_24 id_25 id_26 id_27
0 2 0 4 5 0 0 8 0 10 0 0 0 14 0 0 17 0 0 0 21 0 0 0 0 0 0
我想運行一個SELECT語句來獲得最多8列> 0(絕不會超過8)的最佳或至少是功能性的方法? 如果沒有8個值> 0,則允許NULLS。 因此,上面的結果表將是。
col1 col2 col3 col4 col5 col6 col7 col8
2 4 5 8 10 14 17 21
如果您可以忍受列中的結果,那么這是一種簡單的方法:
select top 8 v.col
from table t cross apply
values ((t.id_1), (t.id_2), . . ., (t.id_27)) as v(col)
where v.col <> 0;
所有數據都獲得8。 如果你想要每行8個,那么你需要一個行標識符。 你可以使用窗口函數:
select t.id, v.col
from (select t.id, v.col,
row_number() over (partition by t.id order by (select null)) as seqnum
from table t cross apply
values ((t.id_1), (t.id_2), . . ., (t.id_27)) as v(col)
where col <> 0
) t
where seqnum <= 8;
最后,您可以將它們轉回一行。 我傾向於使用條件聚合來做到這一點:
select t.id,
max(case when seqnum = 1 then v.col end) as val1,
max(case when seqnum = 2 then v.col end) as val2,
max(case when seqnum = 3 then v.col end) as val3,
max(case when seqnum = 4 then v.col end) as val4,
max(case when seqnum = 5 then v.col end) as val5,
max(case when seqnum = 6 then v.col end) as val6,
max(case when seqnum = 7 then v.col end) as val7,
max(case when seqnum = 8 then v.col end) as val8
from (select t.id, v.col,
row_number() over (partition by t.id order by (select null)) as seqnum
from table t cross apply
values ((t.id_1), (t.id_2), . . ., (t.id_27)) as v(col)
where col <> 0
) t
where seqnum <= 8
group by id;
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.