i has a table:TestTable, this table only has one field: value,i insert same datas:
value
------------
ccc
aa
111
bbb
------------
i run:
select * from TestTable
开发者_如何学编程can show my result order by:
ccc
aa
111
bbb
now,i want get this result DESC:
bbb
111
aa
ccc
how to create this sql?
select * from TestTable order by (by what?) DESC
thak you!
There is no automatic "creation order" identifier that could be used in an order statement. You should use an auto_increment
column to number your records. You can then order by that column.
MySQL docs on auto_increment
Sound like you want to sort using a custom sort order. Two approaches spring to mind: 1) put the sort order in a table and use that table in the query; 2) use a delimited string (assuming the number of values in the domain is small, stable and the values of similar and 'narrow' widths).
Please excuse the SQL Server syntax but fairly standard and hopefully you get the general idea:
e.g. 1
WITH MyTable (ID, data_col)
AS
(
SELECT ID, data_col
FROM (
VALUES (1, 'aa'),
(2, '111'),
(3, 'ccc'),
(4, 'bbb'),
(5, '111'),
(6, 'aa'),
(7, '111'),
(8, 'bbb')
) AS MyTable (ID, data_col)
),
MyDomainWithSortOrder (domain_col, sort_seq)
AS
(
SELECT ID, domain_col
FROM (
VALUES ('bbb', 1),
('111', 2),
('aa', 3),
('ccc', 4)
) AS MyDomainWithSortOrder (ID, domain_col)
)
SELECT T1.ID, T1.data_col, D1.sort_seq
FROM MyTable AS T1
INNER JOIN MyDomainWithSortOrder AS D1
ON T1.data_col = D1.domain_col
ORDER
BY sort_seq;
e.g. 2
WITH MyTable (ID, data_col)
AS
(
SELECT ID, data_col
FROM (
VALUES (1, 'aa'),
(2, '111'),
(3, 'ccc'),
(4, 'bbb'),
(5, '111'),
(6, 'aa'),
(7, '111'),
(8, 'bbb')
) AS MyTable (ID, data_col)
)
SELECT ID, data_col
FROM MyTable
ORDER
BY CHARINDEX(CAST(data_col + ' ' AS CHAR(3)), 'bbb111aa ccc');
Would something like this work?
SELECT @rownum := @rownum +1 `rank`,
T.*
FROM TestTable T,
( SELECT @rownum :=0 ) T
ORDER BY `rank` DESC
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