Usage of (+ in oracle

The plus sign ( ) operator in Oracle can be used to: connect strings, numbers, dates and time intervals; handle NULL values ​​and convert NULL to non-NULL values; convert data types to string types.

Usage of plus sign ( ) operator in Oracle

The plus sign ( ) operator in Oracle has many Uses include:

1. Connecting strings

SELECT 'Hello' || ' World';
-- 输出：HelloWorld

2. Connecting numbers

SELECT 12 + 34;
-- 输出：46

3 . Connection date

SELECT DATE '2023-01-01' + INTERVAL '1' DAY;
-- 输出：2023-01-02

4. Connection time interval

SELECT INTERVAL '1' HOUR + INTERVAL '30' MINUTE;
-- 输出：INTERVAL '1:30' HOUR TO MINUTE

5. NULL processing

plus sign( ) operator can convert NULL values ​​to non-NULL values, as follows:

• String: NULL string = string
• Number : NULL number = number
• Date: NULL date = date
• Time interval: NULL time interval = Time interval

SELECT NULL + 'Hello';
-- 输出：Hello

SELECT NULL + 12;
-- 输出：12

6. Convert data type

The plus sign ( ) operator can implicitly convert the data type to a string type.

SELECT '12' + 34;
-- 输出：'1234'

Note:

• The plus sign () operator has higher priority than the multiplication sign (*) and division sign (/).
• For null or NULL values, the behavior of the plus () operator follows Oracle's null value handling rules.

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