Mysql 具有order by和limit的sql组查询

我的桌子结构如下

| id   | cmp      | empid | empname | ttm  
+------+----------+-------+---------+------
|    2 | xyz      | 12    | swap    |    2 
|    2 | xyz      | 12    | sag     |    3
|    2 | xyz      | 14    | azr     |    1 
|    3 | pqr      | 2     | ron     |    2 
|    3 | pqr      | 22    | rah     |    1 
|    3 | pqr      | 32    | pra     |    5 

(select * from test.companies where id = '2' order by ttm desc limit 2)
union
(select * from test.companies where id = '3' order by ttm desc limit 2);

| id   | cmp      | empid | empname | ttm  
+------+----------+-------+---------+------
|    2 | wissen   | 12    | sag     |    3
|    2 | wissen   | 12    | swap    |    2 
|    3 | prolinkd | 32    | pra     |    5
|    3 | prolinkd | 2     | ron     |    2 

| id   | cmp      | empid | empname | ttm  
+------+----------+-------+---------+------
|    3 | prolinkd | 32    | pra     |    5
|    3 | prolinkd | 2     | ron     |    2
|    2 | wissen   | 12    | sag     |    3 
|    2 | wissen   | 12    | swap    |    2 

我已经做了如下类似的查询

| id   | cmp      | empid | empname | ttm  
+------+----------+-------+---------+------
|    2 | xyz      | 12    | swap    |    2 
|    2 | xyz      | 12    | sag     |    3
|    2 | xyz      | 14    | azr     |    1 
|    3 | pqr      | 2     | ron     |    2 
|    3 | pqr      | 22    | rah     |    1 
|    3 | pqr      | 32    | pra     |    5 

(select * from test.companies where id = '2' order by ttm desc limit 2)
union
(select * from test.companies where id = '3' order by ttm desc limit 2);

| id   | cmp      | empid | empname | ttm  
+------+----------+-------+---------+------
|    2 | wissen   | 12    | sag     |    3
|    2 | wissen   | 12    | swap    |    2 
|    3 | prolinkd | 32    | pra     |    5
|    3 | prolinkd | 2     | ron     |    2 

| id   | cmp      | empid | empname | ttm  
+------+----------+-------+---------+------
|    3 | prolinkd | 32    | pra     |    5
|    3 | prolinkd | 2     | ron     |    2
|    2 | wissen   | 12    | sag     |    3 
|    2 | wissen   | 12    | swap    |    2 

它将给出如下输出

| id   | cmp      | empid | empname | ttm  
+------+----------+-------+---------+------
|    2 | xyz      | 12    | swap    |    2 
|    2 | xyz      | 12    | sag     |    3
|    2 | xyz      | 14    | azr     |    1 
|    3 | pqr      | 2     | ron     |    2 
|    3 | pqr      | 22    | rah     |    1 
|    3 | pqr      | 32    | pra     |    5 

(select * from test.companies where id = '2' order by ttm desc limit 2)
union
(select * from test.companies where id = '3' order by ttm desc limit 2);

| id   | cmp      | empid | empname | ttm  
+------+----------+-------+---------+------
|    2 | wissen   | 12    | sag     |    3
|    2 | wissen   | 12    | swap    |    2 
|    3 | prolinkd | 32    | pra     |    5
|    3 | prolinkd | 2     | ron     |    2 

| id   | cmp      | empid | empname | ttm  
+------+----------+-------+---------+------
|    3 | prolinkd | 32    | pra     |    5
|    3 | prolinkd | 2     | ron     |    2
|    2 | wissen   | 12    | sag     |    3 
|    2 | wissen   | 12    | swap    |    2 

但我希望输出如下

| id   | cmp      | empid | empname | ttm  
+------+----------+-------+---------+------
|    2 | xyz      | 12    | swap    |    2 
|    2 | xyz      | 12    | sag     |    3
|    2 | xyz      | 14    | azr     |    1 
|    3 | pqr      | 2     | ron     |    2 
|    3 | pqr      | 22    | rah     |    1 
|    3 | pqr      | 32    | pra     |    5 

(select * from test.companies where id = '2' order by ttm desc limit 2)
union
(select * from test.companies where id = '3' order by ttm desc limit 2);

| id   | cmp      | empid | empname | ttm  
+------+----------+-------+---------+------
|    2 | wissen   | 12    | sag     |    3
|    2 | wissen   | 12    | swap    |    2 
|    3 | prolinkd | 32    | pra     |    5
|    3 | prolinkd | 2     | ron     |    2 

| id   | cmp      | empid | empname | ttm  
+------+----------+-------+---------+------
|    3 | prolinkd | 32    | pra     |    5
|    3 | prolinkd | 2     | ron     |    2
|    2 | wissen   | 12    | sag     |    3 
|    2 | wissen   | 12    | swap    |    2 

表示将首先显示哪个公司具有最大ttm

如果有人知道，请回复

---

谢谢

我想这会有用的：

SELECT * FROM (

    (select * from test.companies where id = '2' order by ttm desc limit 2)
    union
    (select * from test.companies where id = '3' order by ttm desc limit 2)

) as myunion ORDER BY ttm;

---

获取您需要的，并通过ttm订购。

外观和声音都很难看，但它应该满足您的需要。它为每个记录的公司检索“maxttm”，然后在排序中使用该值，允许您根据公司的最高ttm为其分配优先级

SELECT * FROM (
    (SELECT *,
        (SELECT ttm FROM test.companies ic WHERE ic.id = oc.id ORDER BY ttm DESC LIMIT 1) AS maxttm
        FROM test.companies oc WHERE id = '2' ORDER BY ttm DESC LIMIT 2)
    UNION
    (SELECT *,
        (SELECT ttm FROM test.companies ic WHERE ic.id = oc.id ORDER BY ttm DESC LIMIT 1) AS maxttm
        FROM test.companies oc WHERE id = '3' ORDER BY ttm DESC LIMIT 2)
) AS myunion ORDER BY maxttm, id;

---

另外，多亏了inti，我无耻地将其作为我的查询的基础。

基于示例数据，我认为这不匹配。似乎他希望TTM值较高的公司的所有记录都排在第一位（例如，公司3的TTM值最高，所以公司3的所有记录都排在第一位）。另外，如果您这样做，我不明白如何将每个ID限制为前2条记录。感谢上面的查询再次为我提供了帮助谢谢。@Swapnil Sonawane所以您希望公司分组，但按其最大ttm值排序，很好，谢天谢地@Jeff Parker理解了：）