ORDER BY single column in SQL - Step-by-Step Execution

Concept Flow - ORDER BY single column

Start Query

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Fetch Rows

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Sort Rows by Column

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Return Sorted Rows

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End Query

The query fetches rows from a table, sorts them by one column, then returns the sorted rows.

Execution Sample

SQL

SELECT name, age FROM people ORDER BY age;

This query selects names and ages from the people table and sorts the results by age in ascending order.

Execution Table

Step	Action	Rows Before	Sort Column	Rows After	Notes
1	Start query execution	N/A	N/A	N/A	Query begins
2	Fetch all rows from people	[{"name":"Alice","age":30},{"name":"Bob","age":25},{"name":"Carol","age":35}]	age	[{"name":"Alice","age":30},{"name":"Bob","age":25},{"name":"Carol","age":35}]	Rows fetched unsorted
3	Sort rows by age ascending	[{"name":"Alice","age":30},{"name":"Bob","age":25},{"name":"Carol","age":35}]	age	[{"name":"Bob","age":25},{"name":"Alice","age":30},{"name":"Carol","age":35}]	Rows sorted by age
4	Return sorted rows	[{"name":"Bob","age":25},{"name":"Alice","age":30},{"name":"Carol","age":35}]	age	[{"name":"Bob","age":25},{"name":"Alice","age":30},{"name":"Carol","age":35}]	Query ends with sorted output

💡 All rows sorted by age ascending, query completes.

Variable Tracker

Variable	Start	After Fetch	After Sort	Final
rows	N/A	[{"name":"Alice","age":30},{"name":"Bob","age":25},{"name":"Carol","age":35}]	[{"name":"Bob","age":25},{"name":"Alice","age":30},{"name":"Carol","age":35}]	[{"name":"Bob","age":25},{"name":"Alice","age":30},{"name":"Carol","age":35}]

Key Moments - 2 Insights

Why do the rows change order only after the sorting step?

Because initially rows are fetched in the order stored in the table (see step 2). The ORDER BY clause sorts them afterward (step 3), changing their order before returning.

Does ORDER BY change the data in the table?

No, ORDER BY only changes the order of rows in the query result, not the actual data stored in the table. This is shown by rows before and after sorting in the execution table.

Visual Quiz - 3 Questions

Look at the execution table, what is the order of rows after step 3?

A [{"name":"Carol","age":35},{"name":"Alice","age":30},{"name":"Bob","age":25}]

B [{"name":"Alice","age":30},{"name":"Bob","age":25},{"name":"Carol","age":35}]

C [{"name":"Bob","age":25},{"name":"Alice","age":30},{"name":"Carol","age":35}]

D [{"name":"Alice","age":30},{"name":"Carol","age":35},{"name":"Bob","age":25}]

💡 Hint

Check the 'Rows After' column in step 3 of the execution table.

At which step does the query actually return the sorted rows?

A Step 4

B Step 2

C Step 3

D Step 1

💡 Hint

Look at the 'Action' column describing when rows are returned.

If the ORDER BY clause was removed, how would the 'Rows After' in step 3 change?

A Rows would be sorted by age ascending

B Rows would remain unsorted as in step 2

C Rows would be sorted by age descending

D Rows would be empty

💡 Hint

Without ORDER BY, rows keep their original order after fetching.

Concept Snapshot

ORDER BY single column syntax:
SELECT columns FROM table ORDER BY column_name [ASC|DESC];
By default, ORDER BY sorts ascending (ASC).
It sorts the query result rows by the specified column.
Does not change table data, only output order.
Useful to organize results for reading or further processing.

Full Transcript

This visual execution shows how an SQL query with ORDER BY on a single column works. First, the query starts and fetches all rows from the table unsorted. Then, it sorts these rows by the specified column in ascending order. Finally, it returns the sorted rows as the query result. The variable 'rows' changes from unsorted to sorted after the sorting step. ORDER BY affects only the output order, not the stored data. This step-by-step trace helps beginners see exactly when and how sorting happens in the query execution.