Comparison and differences of SQL syntax between Oracle and DB2

Oracle and DB2 are two commonly used relational database management systems. They have their own unique SQL syntax and characteristics. This article will compare and differ between the SQL syntax of Oracle and DB2, and provide specific code examples.

1. Database connection

In Oracle, use the following statement to connect to the database:

CONNECT username/password@database

And in DB2, the statement to connect to the database is as follows:

CONNECT TO database USER username USING password

2. Create table

In Oracle, the syntax for creating a table is as follows:

CREATE TABLE table_name(
   column1 datatype,
   column2 datatype,
   ...
);

And in DB2, the syntax for creating a table is slightly different:

CREATE TABLE schema.table_name(
   column1 datatype,
   column2 datatype,
   ...
);

3. Insert data

In Oracle, the syntax for inserting data is as follows:

INSERT INTO table_name(column1, column2, ...) VALUES(value1, value2, ...);

And in DB2, the syntax for inserting data is as follows:

INSERT INTO schema.table_name(column1, column2, ...) VALUES(value1, value2, ...);

4. Update data

In Oracle, the syntax for updating data is as follows:

UPDATE table_name SET column1 = value1, column2 = value2 WHERE condition;

And in DB2, the syntax for updating data is as follows:

UPDATE schema.table_name SET column1 = value1, column2 = value2 WHERE condition;

5. Delete data

In Oracle, the syntax for deleting data is as follows:

DELETE FROM table_name WHERE condition;

And in DB2, the syntax for deleting data is as follows:

DELETE FROM schema.table_name WHERE condition;

6. Query data

In Oracle, the syntax for querying data is as follows:

SELECT column1, column2, ... FROM table_name WHERE condition;

And in DB2, the syntax for querying data is as follows:

SELECT column1, column2, ... FROM schema.table_name WHERE condition;

In summary, although there are some differences in SQL syntax between Oracle and DB2, their basic logic is similar, and both are powerful tools for managing and operating databases. It is very important for developers to understand and master the SQL syntax of different database systems so that database operations can be completed more efficiently.

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