Count Rows With COUNT(*)

Aggregate a result set into a single row that reports how many rows matched.

5/5 supported engines validation-green 1 example 2 scenarios

Docker-validated Not currently validation-green

Example 1

Count rows that match a filter

The WHERE clause limits the rows first, then COUNT(*) collapses the remaining set to one numeric result.

Source table data Rows loaded before the example query runs.

Setup

CREATE TABLE tasks (id INT, status VARCHAR(20));

INSERT INTO
  tasks (id, status)
VALUES
  (1, 'open'),
  (2, 'done'),
  (3, 'open');

Validated query Shared across supported engines.

SQL

SELECT
  COUNT(*) AS total_open
FROM
  tasks
WHERE
  status = 'open';

Expected result Returned rows for the shared example.

total_open
2

All engines return a single-row aggregate result for this example.

Useful when

Where this command helps.

reporting how many records match a condition
checking whether a filtered dataset is empty or large enough to act on

Explanation

What the command is doing.

COUNT(*) is the standard way to count rows. It is especially useful after applying filters, because it reports how many rows remain rather than returning each row individually.

Count Rows With COUNT(*)

Count rows that match a filter

Where this command helps.

What the command is doing.

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