TABLENAME：表格
列：
Id | name | c1 | c2 | c3 | c4 | b1 | b2 | b3 | b4 | time
查询：
Select (case when select count(*) from s1 where s1.b1 = 1
then select top 1 from s1 where s1.b1 = 1 order by time desc
else s2.id
end) as COLUMNONE,
(case when select count(*) from s1 where s1.b2 = 1
then select top 1 from s1 where s1.b2 = 1 order by time desc
else s2.name
end) as COLUMNTWO,
(case when select count(*) from s1 where s1.b3 = 1
then select top 1 from s1 where s1.b3 = 1 order by time desc
else s2.c1
end) as COLUMNTHREE,
(case when select count(*) from s1 where s1.b4 = 1
then select top 1 from s1 where s1.b4 = 1 order by time desc
else s2.c2
end) as COLUMNFOUR
from
table s1, table s2
where s1.id = s2.id;
s1 table records
uniqueId | Id | name | c1 | c2 | c3 | c4 | b1 | b2 | b3 | b4 | time
a 12 abc qw tr cd hi 1 1 1 1 1
b 13 abc qw tr cd hi 1 1 1 1 2
c 14 abc qw tr cd hi 1 1 1 1 3
d 12 null null null cd hi 1 0 0 0 4
e 13 abcef qw tr cd hi 1 1 0 0 5
f 14 null null null cd hi 1 0 0 0 6
g 12 abcji qwer trft cd hi 1 1 1 0 7
h 13 null null null cd hi 1 0 0 0 8
i 14 abc qw tryr cdoi hi 1 0 1 1 9
j 12 abc qw trqw cdpl hi 1 0 0 1 10
k 13 abcij qw tr cd hi 1 1 0 0 11
l 14 abc qw troi cd hi 1 0 1 0 12
s2 table records will contain the latest records
Id | name | c1 | c2 | c3 | c4 | b1 | b2 | b3 | b4 | time
12 abc qw tr cdpl hi 1 0 0 1 10
13 abcij qw tr cd hi 1 1 0 0 11
14 abc qw troi cd hi 1 0 1 0 12
OUTPUT :
Id(COLUMNONE) | name(COLUMNTWO) | c1(COLUMNTHREE) | c2(COLUMNFOUR) |
12 abcji qw trqw
13 abcij qw tr
14 abc qw tryr
如果我有多个选择子查询，有人可以帮助我如何优化吗？