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--- modul:m290:learningunits:lu07:theorie:01 [2024/09/30 12:03] – [Overview of MySQL DML] vdemir
+++ modul:m290:learningunits:lu07:theorie:01 [2024/10/17 12:46] (aktuell) – vdemir
@@ Zeile 1: / Zeile 1: @@
-====== LU07a - SQL-DML: Basics ======
+====== LU08a - SQL-DML: Basics ======
-**Sources**
-  - [[https://www.w3schools.com/sql/sql_insert.asp | W3Schools | INSERT INTO ]]
-  - [[https://www.w3schools.com/sql/sql_update.asp | W3Schools | UPDATE ]]
-  - [[https://www.w3schools.com/sql/sql_delete.asp | W3Schools | DELETE ]]
 ===== Learning Objectives =====
@@ Zeile 22: / Zeile 18: @@
 Each of these commands can be executed **with or without filtering conditions**, affecting either specific rows or all rows within a table.
-===== 1. INSERT Statement =====
-The INSERT command is used to add new records to a table. When using INSERT, it is essential to specify the table and columns where the data will be added.
-** Syntax **
-  INSERT INTO table_name (column1, column2, column3)
-  VALUES (value1, value2, value3);
-** Example **
-  INSERT INTO employees (employee_id, first_name, last_name, hire_date, salary)
-  VALUES (1, 'John', 'Doe', '2023-09-18', 55000);
-===== 2. UPDATE Statement =====
-The UPDATE command is used to modify existing data in a table. It can be executed with or without a WHERE clause, depending on whether you want to update specific rows or all rows.
-==== 2.1 UPDATE with Filter (WHERE Clause) ====
-Using a WHERE clause allows you to target specific rows to update. This ensures that only rows meeting a certain condition are modified.
-**Syntax**
-  UPDATE table_name
-  SET column1 = value1, column2 = value2
-  WHERE condition;
-**Example**
-  UPDATE employees
-  SET salary = 60000
-  WHERE employee_id = 1;
-==== 2.2 UPDATE without Filter ====
-If you omit the WHERE clause, the UPDATE command will modify every row in the table, which can lead to unintended changes, so it must be used with caution.
-**Syntax**
-  UPDATE table_name
-  SET column1 = value1;
-**Example**
-  UPDATE employees
-  SET salary = 70000;
-===== 3. DELETE Statement =====
-The DELETE command is used to remove records from a table. Like UPDATE, it can be run with or without a filter, making it vital to define the condition to avoid unintended data removal.
-==== 3.1 DELETE with Filter (WHERE Clause) ====
-Using a WHERE clause ensures that only specific rows matching the condition will be deleted.
-**Syntax:**
-  DELETE FROM table_name
-  WHERE condition;
-**Example**
-  DELETE FROM employees
-  WHERE employee_id = 1;
-==== 3.2 DELETE without Filter ====
-Omitting the WHERE clause removes all data from the table, so it must be used cautiously. This operation doesn’t remove the table structure, just the rows.
-**Syntax:**
-  DELETE FROM table_name;
-**Example:**
-  DELETE FROM employees;
 ===== Conclusion =====