Tasks for scheduling SQL in Snowflake - Step-by-Step Execution

Process Flow - Tasks for scheduling SQL

Create Task

↓

Define SQL Statement

↓

Set Schedule

↓

Enable Task

↓

Task Runs Automatically

↓

Check Task History

↓

Modify or Disable Task

↓

End

This flow shows how to create a scheduled task in Snowflake: create it, define the SQL, set the schedule, enable it, then it runs automatically on schedule.

Execution Sample

Snowflake

CREATE OR REPLACE TASK my_task
  WAREHOUSE = my_wh
  SCHEDULE = 'USING CRON 0 * * * * UTC'
AS
  INSERT INTO my_table VALUES (CURRENT_TIMESTAMP());

ALTER TASK my_task RESUME;

This code creates a task that runs every hour, inserting the current timestamp into a table, then enables the task.

Process Table

Step	Action	SQL Command	Result	Notes
1	Create task with schedule	CREATE OR REPLACE TASK my_task WAREHOUSE = my_wh SCHEDULE = 'USING CRON 0 * * * * UTC' AS INSERT INTO my_table VALUES (CURRENT_TIMESTAMP());	Task 'my_task' created	Task is defined but not running yet
2	Enable task	ALTER TASK my_task RESUME;	Task 'my_task' enabled	Task will run on schedule now
3	Task runs at scheduled time	Automatic execution	Row inserted into my_table	Task runs every hour at minute 0
4	Check task history	SHOW TASK HISTORY LIKE 'my_task';	Shows past runs and status	Verify task success or errors
5	Modify task schedule	ALTER TASK my_task SET SCHEDULE = 'USING CRON 30 * * * * UTC';	Schedule updated	Task now runs at minute 30 each hour
6	Disable task	ALTER TASK my_task SUSPEND;	Task suspended	Task stops running automatically
7	Exit	-	-	Task scheduling complete

💡 Task suspended or deleted, no further automatic runs

Status Tracker

Variable	Start	After Step 1	After Step 2	After Step 5	After Step 6
Task State	Not created	Created (suspended)	Enabled (running)	Enabled (running, new schedule)	Suspended (not running)
Schedule	None	Every hour at minute 0	Every hour at minute 0	Every hour at minute 30	Every hour at minute 30

Key Moments - 3 Insights

Why does the task not run immediately after creation?

Because after creation, the task is in a suspended state by default (see Step 1 and Step 2). You must explicitly enable it with ALTER TASK ... RESUME to start automatic runs.

How can I change when the task runs?

You can modify the schedule using ALTER TASK ... SET SCHEDULE (see Step 5). The new schedule takes effect after the command.

What happens if I suspend the task?

Suspending the task stops it from running automatically (see Step 6). It remains defined but inactive until resumed.

Visual Quiz - 3 Questions

Look at the execution table, what is the task state after Step 2?

A Enabled and running

B Suspended

C Created but suspended

D Deleted

💡 Hint

Check the 'Result' and 'Notes' columns for Step 2 in the execution table.

At which step does the task schedule change to run at minute 30 each hour?

A Step 3

B Step 5

C Step 4

D Step 6

💡 Hint

Look for the ALTER TASK ... SET SCHEDULE command in the execution table.

If you skip Step 2 (enabling the task), what happens?

A Task runs once and stops

B Task runs immediately after creation

C Task never runs automatically

D Task runs only on demand

💡 Hint

Refer to the key moment about task state after creation and enabling.

Concept Snapshot

Snowflake Tasks schedule SQL commands to run automatically.
Create a task with CREATE TASK, define SQL and schedule.
Enable it with ALTER TASK ... RESUME to start running.
Modify schedule with ALTER TASK ... SET SCHEDULE.
Suspend with ALTER TASK ... SUSPEND to stop running.

Full Transcript

This lesson shows how to schedule SQL commands in Snowflake using Tasks. First, you create a task with a SQL statement and a schedule using a cron expression. The task is created but not running until you enable it with ALTER TASK ... RESUME. Once enabled, the task runs automatically on the schedule, for example every hour. You can check the task's run history to see if it succeeded. If needed, you can change the schedule or suspend the task to stop it from running. This process helps automate repetitive SQL operations in Snowflake.