UPDATE multiple columns in SQL - Step-by-Step Execution

Concept Flow - UPDATE multiple columns

Start UPDATE statement

↓

Specify table to update

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Set new values for multiple columns

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Apply WHERE condition to select rows

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Execute update on selected rows

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Finish and return number of rows updated

The UPDATE statement changes values in multiple columns for rows that meet the WHERE condition.

Execution Sample

SQL

UPDATE employees
SET salary = salary * 1.1, department = 'Sales'
WHERE department = 'Marketing';

This query increases salary by 10% and changes department to 'Sales' for employees in 'Marketing'.

Execution Table

Step	Action	Row ID	Old salary	Old department	New salary	New department	Condition Met	Result
1	Check row	101	50000	Marketing	55000	Sales	Yes	Update applied
2	Check row	102	60000	Sales	60000	Sales	No	No update
3	Check row	103	55000	Marketing	60500	Sales	Yes	Update applied
4	Check row	104	70000	HR	70000	HR	No	No update
5	Finish	-	-	-	-	-	-	2 rows updated

💡 All rows checked; only rows with department 'Marketing' updated.

Variable Tracker

Variable	Start	After Row 101	After Row 102	After Row 103	After Row 104	Final
salary_101	50000	55000	55000	55000	55000	55000
department_101	Marketing	Sales	Sales	Sales	Sales	Sales
salary_102	60000	60000	60000	60000	60000	60000
department_102	Sales	Sales	Sales	Sales	Sales	Sales
salary_103	55000	55000	55000	60500	60500	60500
department_103	Marketing	Marketing	Marketing	Sales	Sales	Sales
salary_104	70000	70000	70000	70000	70000	70000
department_104	HR	HR	HR	HR	HR	HR

Key Moments - 2 Insights

Why are only some rows updated and not all?

Only rows where the WHERE condition is true (department = 'Marketing') are updated, as shown in execution_table rows 1 and 3.

Does the UPDATE change columns not listed in SET?

No, only columns specified in SET are changed. Other columns keep their original values, as seen in rows 2 and 4 where no update occurs.

Visual Quiz - 3 Questions

Look at the execution table, what is the new salary of row 103 after the update?

A 60500

B 55000

C 60000

D 70000

💡 Hint

Check the 'New salary' column for row 103 in the execution_table.

At which step does the condition 'department = Marketing' become false?

A Step 1

B Step 2

C Step 3

D Step 4

💡 Hint

Look at the 'Condition Met' column in execution_table for each step.

If the WHERE clause was removed, how would the execution table change?

A Only rows with salary > 60000 would update

B No rows would be updated

C All rows would be updated

D Only rows with department 'Sales' would update

💡 Hint

Without WHERE, UPDATE applies to all rows, so all would show 'Update applied' in the result.

Concept Snapshot

UPDATE multiple columns syntax:
UPDATE table_name
SET column1 = value1, column2 = value2
WHERE condition;
Only rows matching WHERE are updated.
Columns not listed remain unchanged.

Full Transcript

The UPDATE statement changes values in multiple columns for rows that meet the WHERE condition. In the example, employees in the Marketing department have their salary increased by 10% and their department changed to Sales. The execution table shows each row checked, whether it meets the condition, and if it is updated. Only rows 101 and 103 meet the condition and are updated. The variable tracker shows how salary and department values change step-by-step. Key moments clarify why only some rows update and that only specified columns change. The quiz tests understanding of the updated values, condition checks, and effects of removing the WHERE clause.