我不认为我可以在ORDER BY
函数中使用GROUP_CONCAT
子句。
有谁知道在SQLite
中完成此行为的棘手方法?
之前我看过这个question。但我有一个复杂的查询。
我的陈述如下:
SELECT
c.col1, c.col3, m.col3, m.col4,
count(m.col1), count(re.col2) AS cnt,
GROUP_CONCAT(p.col1 ORDER BY p.col1) AS "Group1",
GROUP_CONCAT(p.col2 ORDER BY p.col1) AS "Group2",
GROUP_CONCAT(CASE WHEN con.col3 is null THEN p.col1 ELSE con.col3 END),
con.col4, con.col5, p.col3
FROM t1 re
INNER JOIN t2 c ON (re.col1 = c.col1)
INNER JOIN t3 p ON (re.col2 = p.col1)
LEFT JOIN t4 con ON (con.col1 = p.col2)
INNER JOIN t5 m ON (m.col1 = c.col5)
GROUP BY re.col1
Group1
和Group2
来自同一个表但不同的列:我想保留Group1
与Group2
的顺序:
table t3
+------+------+
| col1 | col2 |
+------+------+
| 1 | A |
| 2 | B |
| 3 | C |
| 4 | D |
| 5 | E |
+------+------+
所以,如果显示Group1
,2,1,3
Group2
应显示为B,A,C
答案 0 :(得分:8)
SQLite不支持ORDER BY
中的GROUP_CONCAT
,但您实际上可以伪造它:
GROUP_CONCAT(list_order || ':' || value)
然后你需要在代码中拆分结果,以便找回你的排序和价值。
答案 1 :(得分:1)
为避免不确定性,您可以使用递归CTE,如下所示:
sqlite> create table t3(pos,col1,col2);
sqlite> insert into t3 values(1,2,'B'),(2,1,'A'),(3,5,'E');
sqlite> select * from t3;
1|2|B
2|1|A
3|5|E
sqlite>
with
sorted(pos,c1,c2) as (
select row_number() over (order by t3.pos), -- sorting by first column's value
t3.col1, t3.col2
from t3
),
concat(pos,c1,c2) as (
select sorted.pos,sorted.c1,sorted.c2 -- starting with values for first position
from sorted
where sorted.pos=1
union all
select sorted.pos,
concat.c1||','||sorted.c1, -- adding next value from col1
concat.c2||','||sorted.c2 -- adding next value from col2
from concat
join sorted
on concat.pos+1 = sorted.pos -- going through subsequent positions
)
select c1, c2
from concat
order by pos desc
limit 1; -- order by desc limit 1 means 'take the row with largest number'
2,1,5|B,A,E
尽管非常复杂,但此解决方案可确保正确排序,并且可以轻松扩展更多列。排序列可能有空白-sorted
CTE会使其变成适当的整数序列。
请注意,row_number() over (order by...)
可能需要支持窗口功能的最新版本的sqlite。
答案 2 :(得分:0)
这样的事情怎么样?
SELECT
col1, col3, col3, col4,
count(col1), count(re.col2) AS cnt,
GROUP_CONCAT(p.col1) AS "Group1",
GROUP_CONCAT(p.col2) AS "Group2",
GROUP_CONCAT(CASE WHEN con.col3 is null THEN p.col1 ELSE con.col3 END),
con.col4, con.col5, p.col3
FROM (
SELECT
*
FROM t1 re
INNER JOIN t2 c ON (re.col1 = c.col1)
INNER JOIN t3 p ON (re.col2 = p.col1)
LEFT JOIN t4 con ON (con.col1 = p.col2)
INNER JOIN t5 m ON (m.col1 = c.col5)
ORDER BY
p.col1 ASC,
p.col2 ASC
)
GROUP BY re.col1
我已经测试了它,但是如果你可以分享一些数据......
答案 3 :(得分:-3)
我已经尝试了这个并且它完成了工作
SELECT
c.col1, c.col3, m.col3, m.col4,
count(m.col1), count(re.col2) AS cnt,
GROUP_CONCAT(p.col1 ORDER BY p.col1) AS "Group1",
GROUP_CONCAT(p.col2 ORDER BY p.col1) AS "Group2",
GROUP_CONCAT(CASE WHEN con.col3 is null THEN p.col1 ELSE con.col3 END),
con.col4, con.col5, p.col3
FROM t1 re
INNER JOIN t2 c ON (re.col1 = c.col1)
INNER JOIN (
SELECT col1, col2, col3, col4, col5 FROM t3 ORDER BY col1
) AS p ON (re.col2 = p.col1)
LEFT JOIN t4 con ON (con.col1 = p.col2)
INNER JOIN t5 m ON (m.col1 = c.col5)
GROUP BY re.col1