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數(shù)據(jù)庫中update與delete使用表別名的深入研究

更新時(shí)間：2024年10月23日 10:33:48 作者：SarPro

本文介紹了UPDATE和DELETE?SQL語句在Oracle,?SQLite,?PostgreSQL,?MYSQL,?mariadb等數(shù)據(jù)庫系統(tǒng)中的執(zhí)行差異,文中通過代碼介紹的非常詳細(xì),對數(shù)據(jù)庫開發(fā)和維護(hù)人員有指導(dǎo)意義,需要的朋友可以參考下

總結(jié)

Update

SQL語句示例	Oracle	SQLite	PostgreSQL	MYSQL & mariadb
`UPDATE users as a SET a.age = 111 WHERE a.name = 'Alice';`	報(bào)錯(cuò)	報(bào)錯(cuò)	報(bào)錯(cuò)	正常執(zhí)行
`UPDATE users as a SET a.age = 111 WHERE name = 'Alice';`	報(bào)錯(cuò)	報(bào)錯(cuò)	報(bào)錯(cuò)	正常執(zhí)行
`UPDATE users as a SET age = 111 WHERE a.name = 'Alice';`	報(bào)錯(cuò)	正常執(zhí)行	正常執(zhí)行	正常執(zhí)行
`UPDATE users as a SET age = 111 WHERE name = 'Alice';`	報(bào)錯(cuò)	正常執(zhí)行	正常執(zhí)行	正常執(zhí)行

Delete

SQL語句示例	Oracle	SQLite	PostgreSQL	MYSQL & mariadb
`delete from users as a WHERE a.name = 'Alice';`	報(bào)錯(cuò)	報(bào)錯(cuò)	報(bào)錯(cuò)	報(bào)錯(cuò)
`delete from users as a WHERE name = 'Alice';`	報(bào)錯(cuò)	報(bào)錯(cuò)	報(bào)錯(cuò)	報(bào)錯(cuò)

1 Update

1.1 測試用例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;

修改前表內(nèi)容如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

1 ORACLE

執(zhí)行報(bào)錯(cuò)

ORA-00971: missing SET keyword

之后查詢表內(nèi)容未發(fā)生變化，如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

2 sqlite

執(zhí)行報(bào)錯(cuò)

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

之后查詢表內(nèi)容未發(fā)生變化，如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

3 PG

執(zhí)行報(bào)錯(cuò)

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';

之后查詢表內(nèi)容未發(fā)生變化，如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

4 MYSQL & mariadb

執(zhí)行正常

后表內(nèi)容已經(jīng)更新，如下：

name	age
Alice	111
Bob	30
Charlie	35
Alice	111

1.2 測試用例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;

修改前表內(nèi)容如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

1 ORACLE

執(zhí)行報(bào)錯(cuò)

ORA-00971: missing SET keyword

之后查詢表內(nèi)容未發(fā)生變化，如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

2 sqlite

執(zhí)行報(bào)錯(cuò)

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

之后查詢表內(nèi)容未發(fā)生變化，如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

3 PG

執(zhí)行報(bào)錯(cuò)

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';

之后查詢表內(nèi)容未發(fā)生變化，如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

4 MYSQL & mariadb

執(zhí)行正常

后表內(nèi)容已經(jīng)更新，如下：

name	age
Alice	111
Bob	30
Charlie	35
Alice	111

1.3 測試用例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;

修改前表內(nèi)容如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

1 ORACLE

執(zhí)行報(bào)錯(cuò)

ORA-00971: missing SET keyword

之后查詢表內(nèi)容未發(fā)生變化，如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

2 sqlite

執(zhí)行正常

后表內(nèi)容已經(jīng)更新，如下：

name	age
Alice	111
Bob	30
Charlie	35
Alice	111

3 PG

執(zhí)行正常

后表內(nèi)容已經(jīng)更新，如下：

name	age
Bob	30
Charlie	35
Alice	111
Alice	111

4 MYSQL & mariadb

執(zhí)行正常

后表內(nèi)容已經(jīng)更新，如下：

name	age
Alice	111
Bob	30
Charlie	35
Alice	111

1.4 測試用例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;

修改前表內(nèi)容如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

1 ORACLE

執(zhí)行報(bào)錯(cuò)

ORA-00971: missing SET keyword

之后查詢表內(nèi)容未發(fā)生變化，如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

2 sqlite

執(zhí)行正常

后表內(nèi)容已經(jīng)更新，如下：

name	age
Alice	111
Bob	30
Charlie	35
Alice	111

3 PG

執(zhí)行正常

后表內(nèi)容已經(jīng)更新，如下：

name	age
Bob	30
Charlie	35
Alice	111
Alice	111

4 MYSQL & mariadb

執(zhí)行正常

后表內(nèi)容已經(jīng)更新，如下：

name	age
Alice	111
Bob	30
Charlie	35
Alice	111

2 delete

2.1 測試用例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;

修改前表內(nèi)容如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

1 ORACLE

執(zhí)行報(bào)錯(cuò)

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

之后查詢表內(nèi)容未發(fā)生變化，如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

2 sqlite

執(zhí)行報(bào)錯(cuò)

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

之后查詢表內(nèi)容未發(fā)生變化，如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

3 PG

執(zhí)行報(bào)錯(cuò)

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

之后查詢表內(nèi)容未發(fā)生變化，如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

4 MYSQL & mariadb

執(zhí)行報(bào)錯(cuò)

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

之后查詢表內(nèi)容未發(fā)生變化，如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

2.2 測試用例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;

修改前表內(nèi)容如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

1 ORACLE

執(zhí)行報(bào)錯(cuò)

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

之后查詢表內(nèi)容未發(fā)生變化，如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

2 sqlite

執(zhí)行報(bào)錯(cuò)

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

之后查詢表內(nèi)容未發(fā)生變化，如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

3 PG

執(zhí)行報(bào)錯(cuò)

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

之后查詢表內(nèi)容未發(fā)生變化，如下：

name	age
Alice	25
Bob	30
Charlie	35
Alice	40

4 MYSQL & mariadb

執(zhí)行報(bào)錯(cuò)

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

之后查詢表內(nèi)容未發(fā)生變化，如下：