【数据库差异研究】update与delete使用表别名的研究

目录

⚛️总结

☪️1 Update

♋1.1 测试用例UPDATE users as a SET a.age = 111 WHERE a.name = 'Alice';

♏1.2 测试用例UPDATE users as a SET a.age = 111 WHERE name = 'Alice';

♐1.3 测试用例UPDATE users as a SET age = 111 WHERE a.name = 'Alice';

♑1.4 测试用例UPDATE users as a SET age = 111 WHERE name = 'Alice';

☪️2 delete

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♉2.1 测试用例delete users as a from a WHERE a.name = 'Alice';

♈2.2 测试用例delete users as a from a WHERE name = 'Alice';

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⚛️总结

Update

SQL语句示例	Oracle	SQLite	PostgreSQL	MYSQL & mariadb
UPDATE users as a SET a.age = 111 WHERE a.name = 'Alice';	报错	报错	报错	正常执行
UPDATE users as a SET a.age = 111 WHERE name = 'Alice';	报错	报错	报错	正常执行
UPDATE users as a SET age = 111 WHERE a.name = 'Alice';	报错	正常执行	正常执行	正常执行
UPDATE users as a SET age = 111 WHERE name = 'Alice';	报错	正常执行	正常执行	正常执行

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Delete

SQL语句示例	Oracle	SQLite	PostgreSQL	MYSQL & mariadb
delete from users as a WHERE a.name = 'Alice';	报错	报错	报错	报错
delete from users as a WHERE name = 'Alice';	报错	报错	报错	报错

---

☪️1 Update

♋1.1 测试用例UPDATE users as a SET a.age = 111 WHERE a.name = 'Alice';

UPDATE users as a SET a.age = 111 WHERE a.name = 'Alice';

CREATE TABLE users (
    name VARCHAR(255) NOT NULL,
    age INT
);

INSERT INTO users (name, age) VALUES ('Alice', 25);
INSERT INTO users (name, age) VALUES ('Bob', 30);
INSERT INTO users (name, age) VALUES ('Charlie', 35);
INSERT INTO users (name, age) VALUES ('Alice', 40);

SELECT * FROM users;
UPDATE users as a SET a.age = 111 WHERE a.name = 'Alice';
SELECT * FROM users;

修改前表内容如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

---

1 ORACLE

执行报错

ORA-00971: missing SET keyword 

之后查询表内容未发生变化，如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

---

2 sqlite

执行报错

Error: near line 12: near ".": syntax error

之后查询表内容未发生变化，如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

---

3 PG

执行报错

psql:commands.sql:12: ERROR:  column "a" of relation "users" does not exist
LINE 1: UPDATE users as a SET a.age = 111 WHERE a.name = 'Alice';

之后查询表内容未发生变化，如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

---

4 MYSQL & mariadb

执行正常

后表内容已经更新，如下：

name	age
Alice	111
Bob	30
Charlie	35
Alice	111

---

♏1.2 测试用例UPDATE users as a SET a.age = 111 WHERE name = 'Alice';

UPDATE users as a SET a.age = 111 WHERE name = 'Alice';

CREATE TABLE users (
    name VARCHAR(255) NOT NULL,
    age INT
);

INSERT INTO users (name, age) VALUES ('Alice', 25);
INSERT INTO users (name, age) VALUES ('Bob', 30);
INSERT INTO users (name, age) VALUES ('Charlie', 35);
INSERT INTO users (name, age) VALUES ('Alice', 40);

SELECT * FROM users;
UPDATE users as a SET a.age = 111 WHERE name = 'Alice';
SELECT * FROM users;

修改前表内容如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

---

1 ORACLE

执行报错

ORA-00971: missing SET keyword 

之后查询表内容未发生变化，如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

---

2 sqlite

 执行报错

Error: near line 12: near ".": syntax error

之后查询表内容未发生变化，如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

---

3 PG

  执行报错

psql:commands.sql:12: ERROR:  column "a" of relation "users" does not exist
LINE 1: UPDATE users as a SET a.age = 111 WHERE name = 'Alice';

之后查询表内容未发生变化，如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

---

4 MYSQL & mariadb

执行正常

后表内容已经更新，如下：

name	age
Alice	111
Bob	30
Charlie	35
Alice	111

---

♐1.3 测试用例UPDATE users as a SET age = 111 WHERE a.name = 'Alice';

UPDATE users as a SET age = 111 WHERE a.name = 'Alice';

CREATE TABLE users (
    name VARCHAR(255) NOT NULL,
    age INT
);

INSERT INTO users (name, age) VALUES ('Alice', 25);
INSERT INTO users (name, age) VALUES ('Bob', 30);
INSERT INTO users (name, age) VALUES ('Charlie', 35);
INSERT INTO users (name, age) VALUES ('Alice', 40);

SELECT * FROM users;
UPDATE users as a SET age = 111 WHERE a.name = 'Alice';
SELECT * FROM users;

修改前表内容如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

---

1 ORACLE

 执行报错

ORA-00971: missing SET keyword 

之后查询表内容未发生变化，如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

---

2 sqlite

执行正常

后表内容已经更新，如下：

name	age
Alice	111
Bob	30
Charlie	35
Alice	111

---

3 PG

执行正常

后表内容已经更新，如下：

name	age
Bob	30
Charlie	35
Alice	111
Alice	111

---

4 MYSQL & mariadb

执行正常

后表内容已经更新，如下：

name	age
Alice	111
Bob	30
Charlie	35
Alice	111

---

♑1.4 测试用例UPDATE users as a SET age = 111 WHERE name = 'Alice';

UPDATE users as a SET age = 111 WHERE name = 'Alice';

CREATE TABLE users (
    name VARCHAR(255) NOT NULL,
    age INT
);

INSERT INTO users (name, age) VALUES ('Alice', 25);
INSERT INTO users (name, age) VALUES ('Bob', 30);
INSERT INTO users (name, age) VALUES ('Charlie', 35);
INSERT INTO users (name, age) VALUES ('Alice', 40);

SELECT * FROM users;
UPDATE users as a SET age = 111 WHERE name = 'Alice';
SELECT * FROM users;

修改前表内容如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

---

1 ORACLE

 执行报错

ORA-00971: missing SET keyword 

之后查询表内容未发生变化，如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

---

2 sqlite

执行正常

后表内容已经更新，如下：

name	age
Alice	111
Bob	30
Charlie	35
Alice	111

---

3 PG

执行正常

后表内容已经更新，如下：

name	age
Bob	30
Charlie	35
Alice	111
Alice	111

---

4 MYSQL & mariadb

执行正常

后表内容已经更新，如下：

name	age
Alice	111
Bob	30
Charlie	35
Alice	111

---

☪️2 delete

♉2.1 测试用例delete users as a from a WHERE a.name = 'Alice';

delete users as a from a WHERE a.name = 'Alice';

CREATE TABLE users (
    name VARCHAR(255) NOT NULL,
    age INT
);

INSERT INTO users (name, age) VALUES ('Alice', 25);
INSERT INTO users (name, age) VALUES ('Bob', 30);
INSERT INTO users (name, age) VALUES ('Charlie', 35);
INSERT INTO users (name, age) VALUES ('Alice', 40);

SELECT * FROM users;
delete users as a from a WHERE a.name = 'Alice';
SELECT * FROM users;

修改前表内容如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

---

1 ORACLE

 执行报错

ORA-03048: SQL reserved word 'AS' is not syntactically valid following 'delete
users '

之后查询表内容未发生变化，如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

---

2 sqlite

 执行报错

Error: near line 12: near "users": syntax error

之后查询表内容未发生变化，如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

---

3 PG

 执行报错

psql:commands.sql:12: ERROR:  syntax error at or near "users"
LINE 1: delete users as a from a WHERE a.name = 'Alice';

 之后查询表内容未发生变化，如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

---

4 MYSQL & mariadb

 执行报错

ERROR 1064 (42000) at line 12: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'as a from a WHERE a.name = 'Alice'' at line 1

 之后查询表内容未发生变化，如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

---

♈2.2 测试用例delete users as a from a WHERE name = 'Alice';

delete users as a from a WHERE name = 'Alice';

CREATE TABLE users (
    name VARCHAR(255) NOT NULL,
    age INT
);

INSERT INTO users (name, age) VALUES ('Alice', 25);
INSERT INTO users (name, age) VALUES ('Bob', 30);
INSERT INTO users (name, age) VALUES ('Charlie', 35);
INSERT INTO users (name, age) VALUES ('Alice', 40);

SELECT * FROM users;
delete users as a from a WHERE name = 'Alice';
SELECT * FROM users;

修改前表内容如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

---

1 ORACLE

 执行报错

ORA-03048: SQL reserved word 'AS' is not syntactically valid following 'delete
users '

之后查询表内容未发生变化，如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

---

2 sqlite

 执行报错

Error: near line 12: near "users": syntax error

之后查询表内容未发生变化，如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

---

3 PG

 执行报错

psql:commands.sql:12: ERROR:  syntax error at or near "users"
LINE 1: delete users as a from a WHERE name = 'Alice';

 之后查询表内容未发生变化，如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

---

4 MYSQL & mariadb

 执行报错

ERROR 1064 (42000) at line 12: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'as a from a WHERE name = 'Alice'' at line 1

 之后查询表内容未发生变化，如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

---

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