如何在union之前在mysql中插入一行？

Question

說我有以下幾點：

CREATE TABLE newtable AS (
SELECT @rownum:=@rownum+1 as rownum, name, age FROM (
    SELECT name, age FROM clubAmembers 
    UNION 
    SELECT name, age FROM clubBmembers 
) 
) AS atable 

我怎樣才能使這樣我可以「粘在新的一行在表的開頭」之前的SELECT聯盟使得它將與啓動：

rownum | name| age 
1 | "Jordan" | 6 <-- This is an arbitrarily inserted record with name="Jordan" age="6" that is not a part of any of the clubAmembers or clubBmembers table. 

表格的其餘部分（rownum 2及以上）將包含與clubAmembers然後clubBmembers的聯盟的實際結果。

基本上我要找： CREATE TABLE INSERT a row「Jordan」| 6 使用聯合執行選擇，以使第一個之後的行以「rownum = 2」開頭，來自clubAmembers的所有數據等。

如何最好地執行此操作？

Answer 1

「在表的開始處」對於關係數據庫並不真正有意義，因爲直到使用ORDER BY子句時纔會保證返回訂單結果，此時磁盤上的訂單無論如何都會成爲一個爭論點。

在你的情況，因爲你想在你的結果子句來保證訂單（因此訂貨@rownum，你將不得不使用ORDER BY喜歡的東西：

CREATE TABLE newtable AS (
    SELECT @rownum:=@rownum+1 as rownum, name, age 
    FROM (
     SELECT 'Jordan' AS name, 6 AS age, 0 AS ord 
     UNION 
     SELECT name, age, 1 AS ord FROM clubAmembers 
     UNION 
     SELECT name, age, 1 AS ord FROM clubBmembers 
     ORDER BY ord 
    ) 
) AS atable 

注意，在任何時候，做這樣的保證那麼clubAmembers中的行將比clubBmembers中的行具有更低的rownum。如果你想保證clubAmembers具有較低rownum，同時保持UNION（相對於UNION ALL）語義，您可以使用以下命令：

CREATE TABLE newtable AS (
    SELECT @rownum:=@rownum+1 as rownum, name, age 
    FROM (
     SELECT 'Jordan' AS name, 6 AS age, 0 AS ord 
     UNION ALL 
     SELECT name, age, 1 AS ord FROM clubAmembers 
     UNION ALL 
     SELECT name, age, 2 AS ord FROM clubBmembers AS b 
     WHERE NOT EXISTS(SELECT 1 FROM clubAmembers AS a 
         WHERE a.name = b.name AND a.age = b.age) 
     ORDER BY ord 
    ) 
) AS atable 

注意如果{name，age}可以在clubXmembers表內被複制，你將需要添加DISTINCT：

... 
SELECT DISTINCT name, age, 1 AS ord FROM clubAmembers 
UNION ALL 
... 

---

按照註釋中的要求，如果你有一個clubCmembers表，你會怎麼做：

CREATE TABLE newtable AS (
    SELECT @rownum:=@rownum+1 as rownum, name, age 
    FROM (
     SELECT 'Jordan' AS name, 6 AS age, 0 AS ord 
     UNION ALL 
     SELECT name, age, 1 AS ord FROM clubAmembers 
     UNION ALL 
     SELECT name, age, 2 AS ord FROM clubBmembers AS b 
     WHERE NOT EXISTS(SELECT 1 FROM clubAmembers AS a 
         WHERE a.name = b.name AND a.age = b.age) 
     SELECT name, age, 3 AS ord FROM clubCmembers AS c 
     WHERE NOT EXISTS(SELECT 1 FROM clubAmembers AS a 
         WHERE a.name = c.name AND a.age = c.age) 
     AND NOT EXISTS(SELECT 1 FROM clubBmembers AS b 
         WHERE b.name = c.name AND b.age = c.age) 
     ORDER BY ord 
    ) 
) AS atable 

Answer 2

我不確定我是否正確。但你爲什麼不只是添加另一個工會是這樣的：

CREATE TABLE newtable AS (
SELECT @rownum:=@rownum+1 as rownum, name, age FROM (
    SELECT 1, "Jordan", 6 
    UNION ALL 
    SELECT name, age FROM clubAmembers 
    UNION ALL 
    SELECT name, age FROM clubBmembers 
) 
) AS atable 

Answer 3

您可以創建表statmenet從插入statmenet分開：

1. 創建表（你必須知道哪些colums是戈納是有）
2. 插入您的第一個記錄(INSERT INTO .... Values(...)）
3. 用你的聲明，但與INSERT INTO，而不是創建表所示：INSERT INTO YourNewTable.... Values(YourSubQuery)（NR和列的塔伊必須匹配您的子查詢）

Answer 4

這應該做的，我相信：

CREATE TABLE newtable AS (
    SELECT (@rownum:=IFNULL(@rownum,0)+1)+1 as rownum, name, age FROM (
    SELECT name, age FROM clubAmembers 
    UNION 
    SELECT name, age FROM clubBmembers 
) AS s 
    UNION ALL 
    SELECT 1, 'Jordan', 6 
) AS atable 

演示在SQL小提琴：http://sqlfiddle.com/#!2/ab825/6