> ## Documentation Index > Fetch the complete documentation index at: https://docs.risingwave.com/llms.txt > Use this file to discover all available pages before exploring further. # SELECT > Use the `SELECT` command to retrieve rows from a table or materialized view. It returns the rows that satisfy the criteria that you specify with the clauses and conditions in your query. ## Syntax ```js theme={null} [ WITH clause ] SELECT [ ALL | DISTINCT [ ON ( expression [, ...] ) ]] [ [table_name.]* [ EXCEPT ( [table_name.]except_column, ... ] ) ] | expression [ AS output_name ] [ , expression [ AS output_name ] ... ] ] [ VALUES clause ] [ FROM from_item [ , from_item ...] ] [ WHERE condition ] [ GROUP BY grouping_expression [ , grouping_expression ... ] ] [ HAVING condition ] [ ORDER BY sort_expression [ ASC | DESC ] [ NULLS { FIRST | LAST } ] [ , ... ] ] [ LIMIT count_number ] [ OFFSET start [ ROW | ROWS ] ]; ``` Where `from_item` can be: ```js theme={null} table_name [ [ AS ] alias [ ( column_alias_list ) ] ] window_type ( table_name, col_name, interval_expression ) [ [ AS ] alias [ ( column_alias_list ) ] ] ( SELECT ) [ [ AS ] alias [ ( column_alias_list ) ] ] from_item join_type from_item [ ON join_condition ] ``` ## Parameters | Parameter or clause | Description | | :--------------------- | :-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | **WITH** clause | Provides a way to write supplemental statements for a larger query. For more information, see [WITH clause](/sql/query-syntax/with-clause). | | **DISTINCT** clause | This clause eliminates duplicate rows from the result. SELECT DISTINCT eliminates duplicate rows based on **all selected columns**. SELECT DISTINCT ON allows you to specify expressions or columns and returns only the first row for each unique combination. It requires the use of the ORDER BY clause to determine the first row, and the DISTINCT ON expression must match the leftmost ORDER BY expression. The ORDER BY clause will normally contain additional expressions that determine the desired precedence of rows within each DISTINCT ON group. In this case, this expression can be an alternative with group [topN](/processing/sql/top-n-by-group) when "N=1". See [examples of this clause](#distinct-clause) below to know more about it. | | **EXCEPT** clause | Exclude one or more columns from the result set. By specifying *except\_column*, the query will return all columns in the result set except those specified. | | *expression* | A column or an expression. | | **VALUES** clause | This clause generates one or more rows of data as a table expression. For details, see [VALUES clause](/sql/query-syntax/values-clause). | | *alias* | A temporary alternative name for a table or materialized view in a query. | | *table\_name* | A table or materialized view. | | *grouping\_expression* | Values can be:Input column namesInput column expressions without subqueries or correlated columns | | **ORDER BY** clause | By default, sorting is in ascending (ASC) order, with NULL values treated as the largest. For more information, see [ORDER BY clause](/sql/query-syntax/order-by-clause). | | *sort\_expression* | Values can be:Output column namesOutput column ordinal numbersHidden select expressions | | *count\_number* | The number of results you want to get. | | **OFFSET** clause | The OFFSET clause can only be used with the LIMIT and ORDER BY clauses. | | *(SELECT)* | A SELECT command. You must enclose the subquery in parentheses, and specify an alias. When you include a subquery in the FROM clause, the output of the subquery is used as a temporary view that is only valid in the query. | | *join\_type* | Supported join types: \[INNER] JOINLEFT \[OUTER] JOINRIGHT \[OUTER] JOINFULL \[OUTER] JOINCurrently, only the ON clause is supported for joins. | | *join\_condition* | Conditions for the ON clause that must be met before the two from\_items can be joined. | | *window\_type* | The type of the time window function. Possible values are HOP and TUMBLE. | | *interval\_expression* | The interval expression, in the format of INTERVAL '\'. For example: INTERVAL '2 MINUTES'. The standard SQL format, which places time units outside of quotation marks (for example, INTERVAL '2' MINUTE), is also supported. | | **FROM** clause | Specifies the source of the data on which the query should operate. For more information, see [FROM clause](/sql/query-syntax/from-clause). | | **GROUP BY** clause | Groups rows in a table with identical data, thus eliminating redundancy in the output and aggregates that apply to these groups. For more information, see [GROUP BY clause](/sql/query-syntax/group-by-clause). | | **HAVING** clause | Eliminates group rows that do not satisfy a given condition. For more information, see [HAVING clause](/sql/query-syntax/having-clause). | | **LIMIT** clause | When the ORDER BY clause is not present, the LIMIT clause cannot be used as part of a materialized view. For more information, see [LIMIT clause](/sql/query-syntax/limit-clause). | | **WHERE** clause | Specifies any conditions or filters to apply to your data. For more information, see [WHERE clause](/sql/query-syntax/where-clause). | ## Examples ### `DISTINCT` clause Here is an example of `SELECT DISTINCT`. This query will return only the unique combinations of `first_name` and `last_name`, eliminating any duplicate rows. ```sql theme={null} -- Retrieve the names of employees. SELECT DISTINCT first_name, last_name FROM employees; ``` Here is an example of `SELECT DISTINCT ON`. The query returns the latest order for each unique `customer_id`. `ORDER BY` is used to ensure that the desired row, that is, the row with the latest order date, appears first; otherwise, the returned row will be unpredictable. ```sql theme={null} -- Retrieve the latest order for each unique customer. SELECT DISTINCT ON (customer_id) order_id, customer_id, order_date, total_amount FROM orders ORDER BY customer_id, order_date DESC; ``` ### Example of using several clauses Below are the tables within the same schema that we will be writing queries from. The table `taxi_trips` includes the columns `id`, `distance`, `duration`, and `fare`, where `id` identifies each unique trip. ```yaml theme={null} { "id": VARCHAR, "distance": DOUBLE PRECISION, "duration": DOUBLE PRECISION, "fare": DOUBLE PRECISION } ``` The table `taxi` includes the columns `taxi_id` and `trip_id`, where `trip_id` and `id` in `taxi_trips` are matching fields. ```yaml theme={null} { "taxi_id": VARCHAR, "trip_id": VARCHAR } ``` The table `company` includes the columns `company_id` and `taxi_id`, where `taxi_id` and `taxi_id` in `taxi` are matching fields. ```yaml theme={null} { "company_id": VARCHAR, "taxi_id": VARCHAR } ``` The following query returns the total distance and duration of trips that are beyond the initial charge (\$2.50) of each taxi from the company "Yellow Taxi" and "FabCab". ```sql theme={null} SELECT taxi.taxi_id, sum(trips.distance) AS total_distance, sum(trips.duration) AS total_duration FROM taxi_trips AS trips LEFT JOIN taxi ON trips.id = taxi.trip_id WHERE taxi_id IN ( SELECT taxi_id FROM company WHERE company_id IN ('Yellow Taxi', 'FabCab') ) AND trips.fare > 2.50 GROUP BY taxi_id ORDER BY total_distance, total_duration; ```