How to write oracle for loop

Answer: Oracle FOR loop is used to iterate over a series of rows or values ​​in a table. Syntax: FOR loop_variable IN (SELECT column_name FROM table_name [WHERE condition]) LOOP -- statement END LOOP executed in the loop body; usage: Define a loop variable to store the current row or value in each traversal; conditional filtering: Use the WHERE clause to filter the rows to be traversed; nested loops: Oracle supports nested loops; Alternative method: In addition to FOR loops, CURSOR and FETC can also be used

Oracle for loop

In Oracle, you can use FOR to loop over a series of rows or values ​​in a table.

grammar

 <code class="oracle">FOR loop_variable IN (SELECT column_name FROM table_name [WHERE condition]) LOOP -- 在循环体内执行的语句END LOOP;</code>

Example

The following code snippets all customer names from the customers table and prints them to the console using a FOR loop:

 <code class="oracle">FOR customer_name IN (SELECT customer_name FROM customers) LOOP DBMS_OUTPUT.PUT_LINE(customer_name); END LOOP;</code>

Use variables

loop_variable in the FOR loop is a variable that stores the current row or value in each traversal. This variable can be used to reference data in the loop body.

condition

The WHERE clause is used to filter the rows to be traversed. Return only rows that meet the criteria.

Nested loops

Oracle allows nested loops, where one loop is nested within the other loop. This is used to handle complex data structures.

Alternative Method

In addition to FOR loops, you can also use CURSOR and FETCH statements to traverse data in Oracle.

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