SQL - 插入使用列名作为值

Question

我试图做一个插入成基于选择从表1表2，但我不能得到正确的语法。如下例所示，table1中的列名将驱动插入到table2中的PD_NO列中的值。有人能帮忙吗？

表1：

  (1)  (2)  (3)  (4)  (5)  (6) 
| SEQ | PD_01 | PD_02 | PD_03 | PD_04 | PD_05 | PD_06 | 
|-----+-------+-------+-------+-------+-------+-------| 
| 632 | 10000 | 0 | 500 | 0 | 20000 | 0 | 

表2：

| SEQ | PD_NO | AMT | 
|-----+-------+-------| 
| 632 | 1 | 10000 | 
|-----+-------+-------| 
| 632 | 3 | 500 | 
|-----+-------+-------| 
| 632 | 5 | 20000 | 
|-----+-------+-------| 

我知道，如果我工作的另一个方向（插入的表2到表1内容），我可以做类似如下：

INSERT INTO table1 
SELECT 
     seq, 
     SUM (CASE WHEN pd_no = 1 THEN amt ELSE 0 END) p01_amt, 
     SUM (CASE WHEN pd_no = 2 THEN amt ELSE 0 END) p02_amt, 
     SUM (CASE WHEN pd_no = 3 THEN amt ELSE 0 END) p03_amt, 
     SUM (CASE WHEN pd_no = 4 THEN amt ELSE 0 END) p04_amt, 
     SUM (CASE WHEN pd_no = 5 THEN amt ELSE 0 END) p05_amt, 
     SUM (CASE WHEN pd_no = 6 THEN amt ELSE 0 END) p06_amt 
FROM table2; 

Answer 1

这是一个典型的问题，为此甲骨文11提供UNPIVOT子句中使用查询：

insert into table2(seq, pd_no, amt) 
select seq, pd_no, amt 
from (select * 
      from table1 
      unpivot (amt for pd_no in (pd_01 as 1, pd_02 as 2, pd_03 as 3, pd_04 as 4, pd_05 as 5, pd_06 as 6)) 
     ); 

Answer 2

insert ... select from以1：1的行为基础工作：“选择”选项卡中的一行数据le进入'insert'表的一行。您试图从源表中取一行，并将其转换为目标表中的多行。这不是直接可能的。你必须运行多个插入/选择，一个是要打出每场：

INSERT INTO table2 (SEQ, PD_NO, AMT) SELECT SEQ, PD_01, AMT FROM table1 
INSERT INTO table2 (SEQ, PD_NO, AMT) SELECT SEQ, PD_02, AMT FROM table1 
INSERT INTO table2 (SEQ, PD_NO, AMT) SELECT SEQ, PD_03, AMT FROM table1 
INSERT INTO table2 (SEQ, PD_NO, AMT) SELECT SEQ, PD_04, AMT FROM table1 
etc... 

Answer 3

纯SQL可以这样做：

INSERT INTO table2 (SEQ , PD_NO, AMT) 
SELECT SEQ, 1 as pd_no, PD_01 FROM Table1 
UNION ALL 
SELECT SEQ, 2 as pd_no, PD_02 FROM Table1 
UNION ALL 
SELECT SEQ, 3 as pd_no, PD_03 FROM Table1 
UNION ALL 
SELECT SEQ, 4 as pd_no, PD_04 FROM Table1 
UNION ALL 
SELECT SEQ, 5 as pd_no, PD_05 FROM Table1 
UNION ALL 
SELECT SEQ, 6 as pd_no, PD_06 FROM Table1 

有些数据库已经优化读取源表仅一次的命令（上述查询读源表6次），例如，在ORACLE：

INSERT ALL 
INTO table2 (SEQ , PD_NO, AMT) VALUES (seq, 1, PD_01) 
INTO table2 (SEQ , PD_NO, AMT) VALUES (seq, 2, PD_02) 
INTO table2 (SEQ , PD_NO, AMT) VALUES (seq, 3, PD_03) 
INTO table2 (SEQ , PD_NO, AMT) VALUES (seq, 4, PD_04) 
INTO table2 (SEQ , PD_NO, AMT) VALUES (seq, 5, PD_05) 
INTO table2 (SEQ , PD_NO, AMT) VALUES (seq, 6, PD_06) 
SELECT * FROM table1 

Answer 4

CREATE TABLE 1to6 (i INT PRIMARY KEY); 
INSERT INTO 1to6 (i) VALUES (1), (2), (3), (4), (5), (6); 

INSERT INTO table2 (seq, pd_no, amt) 
SELECT seq, i, 
CASE(i) 
WHEN 1 THEN pd_01 
WHEN 2 THEN pd_02 
WHEN 3 THEN pd_03 
WHEN 4 THEN pd_04 
WHEN 5 THEN pd_05 
WHEN 6 THEN pd_06 
END 
FROM table1 CROSS JOIN 1to6 

---

重新评论：显然，Oracle不支持多行INSERT语法（尽管该语法是标准的SQL-99）。您可以一次插入一行：

INSERT INTO 1to6 (i) VALUES (1); 
INSERT INTO 1to6 (i) VALUES (2); 
INSERT INTO 1to6 (i) VALUES (3); 
INSERT INTO 1to6 (i) VALUES (4); 
INSERT INTO 1to6 (i) VALUES (5); 
INSERT INTO 1to6 (i) VALUES (6);