What does := mean in Oracle?

The assignment operator in Oracle is:=, which is used to assign a value to a variable or expression. It creates a new variable or replaces an existing variable and sets it to the expression on the right side of the equal sign. value.

Assignment operator in Oracle:=

:= is the assignment operator in Oracle, used for Assign a value to a variable or expression. It works by creating a new variable or replacing an existing variable on the left side of the equal sign and setting it to the value of the expression on the right side of the equal sign.

Syntax:

<code>variable_or_expression := expression;</code>

Where:

• variable_or_expression is the variable or expression to be assigned.
• expression is the expression to be assigned to the variable.

Usage example:

<code>-- 创建变量并赋值
DECLARE
  my_variable NUMBER;
BEGIN
  my_variable := 10;
END;</code>

<code>-- 修改现有变量的值
DECLARE
  my_variable NUMBER := 10;
BEGIN
  my_variable := my_variable + 5;
-- my_variable 现在为 15
END;</code>

Note:

• The assignment operator is irreversible. That is, it does not modify the value of the expression on the right.
• If the right-hand expression is NULL, the variable will also be set to NULL.
• Values ​​can only be assigned to variables, not expressions.
• Assignment statements are executed in order. This means that the variable may not have been initialized before being assigned.

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