FROM clause
Description
The
FROM
clause in a query lists the table references (tables, views, and subqueries) that data is selected from. If multiple table references are listed, the tables must be joined, using appropriate syntax in either theFROM
clause or theWHERE
clause. If no join criteria are specified, the system processes the query as a cross-join. (Redshift SQL Language Reference FROM Clause)
The FROM clause is partially supported in Snowflake. Object unpivoting is not currently supported.
Grammar Syntax
FROM table_reference [, ...]
<table_reference> ::=
with_subquery_table_name [ table_alias ]
table_name [ * ] [ table_alias ]
( subquery ) [ table_alias ]
table_reference [ NATURAL ] join_type table_reference
[ ON join_condition | USING ( join_column [, ...] ) ]
table_reference PIVOT (
aggregate(expr) [ [ AS ] aggregate_alias ]
FOR column_name IN ( expression [ AS ] in_alias [, ...] )
) [ table_alias ]
table_reference UNPIVOT [ INCLUDE NULLS | EXCLUDE NULLS ] (
value_column_name
FOR name_column_name IN ( column_reference [ [ AS ]
in_alias ] [, ...] )
) [ table_alias ]
UNPIVOT expression AS value_alias [ AT attribute_alias ]
Sample Source Patterns
Input Code:
CREATE TABLE employee (
id INT,
name VARCHAR(20),
manager_id INT
);
INSERT INTO employee(id, name, manager_id) VALUES
(100, 'Carlos', null),
(101, 'John', 100),
(102, 'Jorge', 101),
(103, 'Kwaku', 101),
(110, 'Liu', 101),
(106, 'Mateo', 102),
(110, 'Nikki', 103),
(104, 'Paulo', 103),
(105, 'Richard', 103),
(120, 'Saanvi', 104),
(200, 'Shirley', 104),
(201, 'Sofía', 102),
(205, 'Zhang', 104);
CREATE TABLE department (
id INT,
name VARCHAR(50),
manager_id INT
);
INSERT INTO department(id, name, manager_id) VALUES
(1, 'HR', 100),
(2, 'Sales', 101),
(3, 'Engineering', 102),
(4, 'Marketing', 103);
SELECT e.name AS employee_name, d.name AS department_name
INTO employees_in_department
FROM employee e
INNER JOIN department d ON e.manager_id = d.manager_id;
Output Code:
CREATE TABLE employee (
id INT,
name VARCHAR(20),
manager_id INT
)
COMMENT = '{ "origin": "sf_sc", "name": "snowconvert", "version": { "major": 0, "minor": 0, "patch": "0" }, "attributes": { "component": "redshift", "convertedOn": "02/06/2025", "domain": "test" }}';
INSERT INTO employee (id, name, manager_id) VALUES
(100, 'Carlos', null),
(101, 'John', 100),
(102, 'Jorge', 101),
(103, 'Kwaku', 101),
(110, 'Liu', 101),
(106, 'Mateo', 102),
(110, 'Nikki', 103),
(104, 'Paulo', 103),
(105, 'Richard', 103),
(120, 'Saanvi', 104),
(200, 'Shirley', 104),
(201, 'Sofía', 102),
(205, 'Zhang', 104);
CREATE TABLE department (
id INT,
name VARCHAR(50),
manager_id INT
)
COMMENT = '{ "origin": "sf_sc", "name": "snowconvert", "version": { "major": 0, "minor": 0, "patch": "0" }, "attributes": { "component": "redshift", "convertedOn": "02/06/2025", "domain": "test" }}';
INSERT INTO department (id, name, manager_id) VALUES
(1, 'HR', 100),
(2, 'Sales', 101),
(3, 'Engineering', 102),
(4, 'Marketing', 103);
CREATE TABLE IF NOT EXISTS employees_in_department AS
SELECT e.name AS employee_name, d.name AS department_name
FROM
employee e
INNER JOIN
department d ON e.manager_id = d.manager_id;
Known Issues
There are no known issues.
Related EWIs.
See SELECT transformation for related EWIs.
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