sql-order-by

问题 I have the following data: id, parent_id 1, 3 2, null 3, 2 4, 2 Where parent_id is a reference to the SAME table. I need to sort these columns so that each record is after its parent (not necessarily immediately after). So I would expect this result: id, parent_id 2, null 3, 2 1, 3 4, 2 I'm guessing there is no clean efficient way to do this without any significant schema changes, but in case anybody can think of a method I'm asking this here. One possible method would be to do multiple

问题 The issue is that using to_char will turn order by date into order by ascii. Example: SELECT foo, bar FROM baz ORDER BY foo; I would like to format foo using to_char, but doing this will affect the order: SELECT to_char(foo,'dd/MM/yyyy') as foo, bar FROM baz ORDER BY foo; Because foo now is of type text. There is a way to correctly do this? Or only in the code? 回答1: You can use a different alias for the formatted column: SELECT to_char(foo,'dd/MM/yyyy') as formatted_foo, bar FROM baz ORDER BY

问题 The issue is that using to_char will turn order by date into order by ascii. Example: SELECT foo, bar FROM baz ORDER BY foo; I would like to format foo using to_char, but doing this will affect the order: SELECT to_char(foo,'dd/MM/yyyy') as foo, bar FROM baz ORDER BY foo; Because foo now is of type text. There is a way to correctly do this? Or only in the code? 回答1: You can use a different alias for the formatted column: SELECT to_char(foo,'dd/MM/yyyy') as formatted_foo, bar FROM baz ORDER BY

问题 The issue is that using to_char will turn order by date into order by ascii. Example: SELECT foo, bar FROM baz ORDER BY foo; I would like to format foo using to_char, but doing this will affect the order: SELECT to_char(foo,'dd/MM/yyyy') as foo, bar FROM baz ORDER BY foo; Because foo now is of type text. There is a way to correctly do this? Or only in the code? 回答1: You can use a different alias for the formatted column: SELECT to_char(foo,'dd/MM/yyyy') as formatted_foo, bar FROM baz ORDER BY

问题 The issue is that using to_char will turn order by date into order by ascii. Example: SELECT foo, bar FROM baz ORDER BY foo; I would like to format foo using to_char, but doing this will affect the order: SELECT to_char(foo,'dd/MM/yyyy') as foo, bar FROM baz ORDER BY foo; Because foo now is of type text. There is a way to correctly do this? Or only in the code? 回答1: You can use a different alias for the formatted column: SELECT to_char(foo,'dd/MM/yyyy') as formatted_foo, bar FROM baz ORDER BY

问题 The issue is that using to_char will turn order by date into order by ascii. Example: SELECT foo, bar FROM baz ORDER BY foo; I would like to format foo using to_char, but doing this will affect the order: SELECT to_char(foo,'dd/MM/yyyy') as foo, bar FROM baz ORDER BY foo; Because foo now is of type text. There is a way to correctly do this? Or only in the code? 回答1: You can use a different alias for the formatted column: SELECT to_char(foo,'dd/MM/yyyy') as formatted_foo, bar FROM baz ORDER BY

问题 The issue is that using to_char will turn order by date into order by ascii. Example: SELECT foo, bar FROM baz ORDER BY foo; I would like to format foo using to_char, but doing this will affect the order: SELECT to_char(foo,'dd/MM/yyyy') as foo, bar FROM baz ORDER BY foo; Because foo now is of type text. There is a way to correctly do this? Or only in the code? 回答1: You can use a different alias for the formatted column: SELECT to_char(foo,'dd/MM/yyyy') as formatted_foo, bar FROM baz ORDER BY

问题 Is there any reason why the following code wouldn't be retrieved in the correct order when using dapper? connection.Query<User>("SELECT id, name " + "FROM user " + "ORDER BY @sort @dir " + "LIMIT @offset, @pageSize; ", new { sort = sortOrder, // sortOrder = "name" dir = sortDirection, // sortDirection = "ASC" offset = pageIndex * pageSize, // offset = 0 pageSize = pageSize // pageSize = 10 }); It always returns without applying the ordering. I could just place the sortOrder and sortDirection

问题 I have to SELECT one row which meets condition1 OR condition2 . However, condition1 is preferable. If there are two rows, where the first one meets condition1 (and does not meet condition2) and second meets condition2 (and does not meet condition1 ) then the first one should be returned. So for SQL: SELECT * FROM table WHERE col1 = 1 OR col2 = 5 LIMIT 1 Will it return the row that meets condition col1 = 1 first? Or will it return rows in random order? If it will be random then how to achieve

问题 I have to SELECT one row which meets condition1 OR condition2 . However, condition1 is preferable. If there are two rows, where the first one meets condition1 (and does not meet condition2) and second meets condition2 (and does not meet condition1 ) then the first one should be returned. So for SQL: SELECT * FROM table WHERE col1 = 1 OR col2 = 5 LIMIT 1 Will it return the row that meets condition col1 = 1 first? Or will it return rows in random order? If it will be random then how to achieve