How to query tables in oracle database

The three methods of querying tables in Oracle database are: using the SELECT statement, syntax: SELECT column name FROM table name WHERE condition ORDER BY sorting condition. Using the DB Browser for SQLite GUI, steps: install, connect to the database, expand the database, and browse data. Using Python and cx_Oracle library, steps: install, import library, connect to database, execute query, extract results.

3 ways to query tables in Oracle database

Method 1: Use the SELECT statement

The SELECT statement is the most common way to query tables in Oracle database. The syntax is:

<code class="sql">SELECT 列名1, 列名2, ...
FROM 表名
WHERE 条件（可选）
ORDER BY 排序条件（可选）</code>

For example, to query all columns in the table named "customers", use the following query:

<code class="sql">SELECT * FROM customers;</code>

Method 2: Use DB Browser for SQLite GUI

DB Browser for SQLite is a free and easy-to-use graphical interface (GUI) for querying Oracle databases. To use it:

1. Install DB Browser for SQLite.
2. Open DB Browser for SQLite and connect to the Oracle database.
3. Under the "Database" tab, expand the database you want to query.
4. Right-click the table you want to query and select "Browse Data".

Method 3: Using Python and the cx_Oracle library

cx_Oracle is a Python library that can be used to interact with Oracle databases. To use it:

1. Install the cx_Oracle library.
2. Import the cx_Oracle library.
3. Connect to Oracle database.
4. Use the execute() method to execute the query.

For example:

<code class="python">import cx_Oracle

# 连接到 Oracle 数据库
connection = cx_Oracle.connect("username", "password", "host:port/database")

# 创建游标
cursor = connection.cursor()

# 执行查询
cursor.execute("SELECT * FROM customers")

# 提取结果
results = cursor.fetchall()

# 打印结果
for row in results:
    print(row)</code>

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