Sql 对单个表使用Merge语句_Sql_Oracle

Sql 对单个表使用Merge语句

sql oracle

Sql 对单个表使用Merge语句,sql,oracle,Sql,Oracle,是否可以对单个表使用merge语句？我想在插入之前检查一下，如果同一组值已经存在，那么应该更新该记录，如果不存在，那么应该插入该记录。我在网上搜索过，但我得到了带有2个表的merge语句的示例。我在一张桌子上试过，但没能得到积极的结果。我试图检查的值将是动态的。我想在我的应用程序中使用此查询我试图检查（在下面的情况下，只检查“主要”列），如果两列匹配，那么应该更新该记录，如果不匹配，那么应该插入该记录我已经创建了一个示例表student。下面是查询 create table student

是否可以对单个表使用merge语句？我想在插入之前检查一下，如果同一组值已经存在，那么应该更新该记录，如果不存在，那么应该插入该记录。我在网上搜索过，但我得到了带有2个表的merge语句的示例。我在一张桌子上试过，但没能得到积极的结果。我试图检查的值将是动态的。我想在我的应用程序中使用此查询

我试图检查（在下面的情况下，只检查“主要”列），如果两列匹配，那么应该更新该记录，如果不匹配，那么应该插入该记录

我已经创建了一个示例表student。下面是查询

create table student (sid int,name varchar(20),major varchar(10),gpa float,tutorid int, PRIMARY KEY (sid))

insert into student values(101,'Bill','CIS',3.45,102)

insert into student values(102,'Mary','CIS',3.1,null)

insert into student values(103,'Sue','Marketing',2.95,102)

insert into student values(104,'Tom','Finanace',3.5,106)

insert into student values(105,'Alex','CIS',2.75,106)

insert into student values(106,'Sam','Marketing',3.25,103)

insert into student values(107,'Joan','Finance',2.9,102)

下面是我正在使用的查询

merge into student a 
using (select name,major from student) b 
on (a.major=b.major)
when matched then
update set a.name='Rahul'
when not matched then
insert(a.SID,a.major) values(123, 'Temp')

我得到下面的错误

ORA-30926:无法在源表中获取一组稳定的行

也许我做的事情完全错了。有人能帮我吗。

使用

选择。。。从中的DUAL
使用

子句生成包含数据的单行：

Oracle 11g R2架构设置：

create table student (
  sid int,
  name varchar(20),
  major varchar(10),
  gpa float,
  tutorid int,
  PRIMARY KEY (sid)
);

insert into student values(101,'Bill','CIS',3.45,102);
insert into student values(102,'Mary','CIS',3.1,null);
insert into student values(103,'Sue','Marketing',2.95,102);
insert into student values(104,'Tom','Finanace',3.5,106);
insert into student values(105,'Alex','CIS',2.75,106);
insert into student values(106,'Sam','Marketing',3.25,103);
insert into student values(107,'Joan','Finance',2.9,102);

merge into student dst
using (
  SELECT 123 AS sid,
         'Rahul' AS name,
         'Temp' AS major
  FROM   DUAL
) src
on (src.major=dst.major)
when matched then
  update set name=src.name
when not matched then
  insert(SID,name,major) values ( src.sid, src.name, src.major )

SELECT * FROM student

| SID |  NAME |     MAJOR |    GPA | TUTORID |
|-----|-------|-----------|--------|---------|
| 101 |  Bill |       CIS |   3.45 |     102 |
| 102 |  Mary |       CIS |    3.1 |  (null) |
| 103 |   Sue | Marketing |   2.95 |     102 |
| 104 |   Tom |  Finanace |    3.5 |     106 |
| 105 |  Alex |       CIS |   2.75 |     106 |
| 106 |   Sam | Marketing |   3.25 |     103 |
| 107 |  Joan |   Finance |    2.9 |     102 |
| 123 | Rahul |      Temp | (null) |  (null) |

查询1：

create table student (
  sid int,
  name varchar(20),
  major varchar(10),
  gpa float,
  tutorid int,
  PRIMARY KEY (sid)
);

insert into student values(101,'Bill','CIS',3.45,102);
insert into student values(102,'Mary','CIS',3.1,null);
insert into student values(103,'Sue','Marketing',2.95,102);
insert into student values(104,'Tom','Finanace',3.5,106);
insert into student values(105,'Alex','CIS',2.75,106);
insert into student values(106,'Sam','Marketing',3.25,103);
insert into student values(107,'Joan','Finance',2.9,102);

merge into student dst
using (
  SELECT 123 AS sid,
         'Rahul' AS name,
         'Temp' AS major
  FROM   DUAL
) src
on (src.major=dst.major)
when matched then
  update set name=src.name
when not matched then
  insert(SID,name,major) values ( src.sid, src.name, src.major )

SELECT * FROM student

| SID |  NAME |     MAJOR |    GPA | TUTORID |
|-----|-------|-----------|--------|---------|
| 101 |  Bill |       CIS |   3.45 |     102 |
| 102 |  Mary |       CIS |    3.1 |  (null) |
| 103 |   Sue | Marketing |   2.95 |     102 |
| 104 |   Tom |  Finanace |    3.5 |     106 |
| 105 |  Alex |       CIS |   2.75 |     106 |
| 106 |   Sam | Marketing |   3.25 |     103 |
| 107 |  Joan |   Finance |    2.9 |     102 |
| 123 | Rahul |      Temp | (null) |  (null) |

查询2：

create table student (
  sid int,
  name varchar(20),
  major varchar(10),
  gpa float,
  tutorid int,
  PRIMARY KEY (sid)
);

insert into student values(101,'Bill','CIS',3.45,102);
insert into student values(102,'Mary','CIS',3.1,null);
insert into student values(103,'Sue','Marketing',2.95,102);
insert into student values(104,'Tom','Finanace',3.5,106);
insert into student values(105,'Alex','CIS',2.75,106);
insert into student values(106,'Sam','Marketing',3.25,103);
insert into student values(107,'Joan','Finance',2.9,102);

merge into student dst
using (
  SELECT 123 AS sid,
         'Rahul' AS name,
         'Temp' AS major
  FROM   DUAL
) src
on (src.major=dst.major)
when matched then
  update set name=src.name
when not matched then
  insert(SID,name,major) values ( src.sid, src.name, src.major )

SELECT * FROM student

| SID |  NAME |     MAJOR |    GPA | TUTORID |
|-----|-------|-----------|--------|---------|
| 101 |  Bill |       CIS |   3.45 |     102 |
| 102 |  Mary |       CIS |    3.1 |  (null) |
| 103 |   Sue | Marketing |   2.95 |     102 |
| 104 |   Tom |  Finanace |    3.5 |     106 |
| 105 |  Alex |       CIS |   2.75 |     106 |
| 106 |   Sam | Marketing |   3.25 |     103 |
| 107 |  Joan |   Finance |    2.9 |     102 |
| 123 | Rahul |      Temp | (null) |  (null) |

：

create table student (
  sid int,
  name varchar(20),
  major varchar(10),
  gpa float,
  tutorid int,
  PRIMARY KEY (sid)
);

insert into student values(101,'Bill','CIS',3.45,102);
insert into student values(102,'Mary','CIS',3.1,null);
insert into student values(103,'Sue','Marketing',2.95,102);
insert into student values(104,'Tom','Finanace',3.5,106);
insert into student values(105,'Alex','CIS',2.75,106);
insert into student values(106,'Sam','Marketing',3.25,103);
insert into student values(107,'Joan','Finance',2.9,102);

merge into student dst
using (
  SELECT 123 AS sid,
         'Rahul' AS name,
         'Temp' AS major
  FROM   DUAL
) src
on (src.major=dst.major)
when matched then
  update set name=src.name
when not matched then
  insert(SID,name,major) values ( src.sid, src.name, src.major )

SELECT * FROM student

| SID |  NAME |     MAJOR |    GPA | TUTORID |
|-----|-------|-----------|--------|---------|
| 101 |  Bill |       CIS |   3.45 |     102 |
| 102 |  Mary |       CIS |    3.1 |  (null) |
| 103 |   Sue | Marketing |   2.95 |     102 |
| 104 |   Tom |  Finanace |    3.5 |     106 |
| 105 |  Alex |       CIS |   2.75 |     106 |
| 106 |   Sam | Marketing |   3.25 |     103 |
| 107 |  Joan |   Finance |    2.9 |     102 |
| 123 | Rahul |      Temp | (null) |  (null) |

使用

选择。。。从中的DUAL
使用

子句生成包含数据的单行：

Oracle 11g R2架构设置：

create table student (
  sid int,
  name varchar(20),
  major varchar(10),
  gpa float,
  tutorid int,
  PRIMARY KEY (sid)
);

insert into student values(101,'Bill','CIS',3.45,102);
insert into student values(102,'Mary','CIS',3.1,null);
insert into student values(103,'Sue','Marketing',2.95,102);
insert into student values(104,'Tom','Finanace',3.5,106);
insert into student values(105,'Alex','CIS',2.75,106);
insert into student values(106,'Sam','Marketing',3.25,103);
insert into student values(107,'Joan','Finance',2.9,102);

merge into student dst
using (
  SELECT 123 AS sid,
         'Rahul' AS name,
         'Temp' AS major
  FROM   DUAL
) src
on (src.major=dst.major)
when matched then
  update set name=src.name
when not matched then
  insert(SID,name,major) values ( src.sid, src.name, src.major )

SELECT * FROM student

| SID |  NAME |     MAJOR |    GPA | TUTORID |
|-----|-------|-----------|--------|---------|
| 101 |  Bill |       CIS |   3.45 |     102 |
| 102 |  Mary |       CIS |    3.1 |  (null) |
| 103 |   Sue | Marketing |   2.95 |     102 |
| 104 |   Tom |  Finanace |    3.5 |     106 |
| 105 |  Alex |       CIS |   2.75 |     106 |
| 106 |   Sam | Marketing |   3.25 |     103 |
| 107 |  Joan |   Finance |    2.9 |     102 |
| 123 | Rahul |      Temp | (null) |  (null) |

查询1：

create table student (
  sid int,
  name varchar(20),
  major varchar(10),
  gpa float,
  tutorid int,
  PRIMARY KEY (sid)
);

insert into student values(101,'Bill','CIS',3.45,102);
insert into student values(102,'Mary','CIS',3.1,null);
insert into student values(103,'Sue','Marketing',2.95,102);
insert into student values(104,'Tom','Finanace',3.5,106);
insert into student values(105,'Alex','CIS',2.75,106);
insert into student values(106,'Sam','Marketing',3.25,103);
insert into student values(107,'Joan','Finance',2.9,102);

merge into student dst
using (
  SELECT 123 AS sid,
         'Rahul' AS name,
         'Temp' AS major
  FROM   DUAL
) src
on (src.major=dst.major)
when matched then
  update set name=src.name
when not matched then
  insert(SID,name,major) values ( src.sid, src.name, src.major )

SELECT * FROM student

| SID |  NAME |     MAJOR |    GPA | TUTORID |
|-----|-------|-----------|--------|---------|
| 101 |  Bill |       CIS |   3.45 |     102 |
| 102 |  Mary |       CIS |    3.1 |  (null) |
| 103 |   Sue | Marketing |   2.95 |     102 |
| 104 |   Tom |  Finanace |    3.5 |     106 |
| 105 |  Alex |       CIS |   2.75 |     106 |
| 106 |   Sam | Marketing |   3.25 |     103 |
| 107 |  Joan |   Finance |    2.9 |     102 |
| 123 | Rahul |      Temp | (null) |  (null) |

查询2：

create table student (
  sid int,
  name varchar(20),
  major varchar(10),
  gpa float,
  tutorid int,
  PRIMARY KEY (sid)
);

insert into student values(101,'Bill','CIS',3.45,102);
insert into student values(102,'Mary','CIS',3.1,null);
insert into student values(103,'Sue','Marketing',2.95,102);
insert into student values(104,'Tom','Finanace',3.5,106);
insert into student values(105,'Alex','CIS',2.75,106);
insert into student values(106,'Sam','Marketing',3.25,103);
insert into student values(107,'Joan','Finance',2.9,102);

merge into student dst
using (
  SELECT 123 AS sid,
         'Rahul' AS name,
         'Temp' AS major
  FROM   DUAL
) src
on (src.major=dst.major)
when matched then
  update set name=src.name
when not matched then
  insert(SID,name,major) values ( src.sid, src.name, src.major )

SELECT * FROM student

| SID |  NAME |     MAJOR |    GPA | TUTORID |
|-----|-------|-----------|--------|---------|
| 101 |  Bill |       CIS |   3.45 |     102 |
| 102 |  Mary |       CIS |    3.1 |  (null) |
| 103 |   Sue | Marketing |   2.95 |     102 |
| 104 |   Tom |  Finanace |    3.5 |     106 |
| 105 |  Alex |       CIS |   2.75 |     106 |
| 106 |   Sam | Marketing |   3.25 |     103 |
| 107 |  Joan |   Finance |    2.9 |     102 |
| 123 | Rahul |      Temp | (null) |  (null) |

：

create table student (
  sid int,
  name varchar(20),
  major varchar(10),
  gpa float,
  tutorid int,
  PRIMARY KEY (sid)
);

insert into student values(101,'Bill','CIS',3.45,102);
insert into student values(102,'Mary','CIS',3.1,null);
insert into student values(103,'Sue','Marketing',2.95,102);
insert into student values(104,'Tom','Finanace',3.5,106);
insert into student values(105,'Alex','CIS',2.75,106);
insert into student values(106,'Sam','Marketing',3.25,103);
insert into student values(107,'Joan','Finance',2.9,102);

merge into student dst
using (
  SELECT 123 AS sid,
         'Rahul' AS name,
         'Temp' AS major
  FROM   DUAL
) src
on (src.major=dst.major)
when matched then
  update set name=src.name
when not matched then
  insert(SID,name,major) values ( src.sid, src.name, src.major )

SELECT * FROM student

| SID |  NAME |     MAJOR |    GPA | TUTORID |
|-----|-------|-----------|--------|---------|
| 101 |  Bill |       CIS |   3.45 |     102 |
| 102 |  Mary |       CIS |    3.1 |  (null) |
| 103 |   Sue | Marketing |   2.95 |     102 |
| 104 |   Tom |  Finanace |    3.5 |     106 |
| 105 |  Alex |       CIS |   2.75 |     106 |
| 106 |   Sam | Marketing |   3.25 |     103 |
| 107 |  Joan |   Finance |    2.9 |     102 |
| 123 | Rahul |      Temp | (null) |  (null) |

您正在更改正在选择的表的内容。不幸的是，PL/SQL中没有

IF EXISTS

，因此您可以尝试使用

SELECT COUNT（*）FROM。。。。。其中…

，仅当select的结果为0时插入。谢谢，@FDavidov。这是我最后的选择。我能做到。但在我的应用程序中，我必须创建两个单独的数据库连接。一个用于select语句，另一个用于update或insert。这是我不想要的。我想通过一个连接来实现这一点。希望你明白我的意思。你（对我）想要的是站在你的手上，希望把你的鞋带系紧。祝你好运@FDavidov非常有趣，它就像是尝试拉伸鞋节一样飞行。为什么不使用存储过程来执行此操作呢？您正在更改正在选择的表的内容。不幸的是，PL/SQL中没有

IF EXISTS

，因此您可以尝试使用

SELECT COUNT（*）FROM。。。。。其中…

，仅当select的结果为0时插入。谢谢，@FDavidov。这是我最后的选择。我能做到。但在我的应用程序中，我必须创建两个单独的数据库连接。一个用于select语句，另一个用于update或insert。这是我不想要的。我想通过一个连接来实现这一点。希望你明白我的意思。你（对我）想要的是站在你的手上，希望把你的鞋带系紧。祝你好运@FDavidov非常有趣，它就像是尝试伸展鞋节飞行。为什么不使用存储过程来实现呢？