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PREPEND

The PREPEND function in SQL is used to prepend an element to a list.

Syntax​

PREPEND(list, element)
  • list: The list to which you want to prepend the element.
  • element: The element that you want to prepend to the list.

Examples​

First, create a table named Prepend with columns for the list, an integer element, and a text element:

CREATE TABLE Prepend (
    id INTEGER,
    items LIST,
    element INTEGER,
    element2 TEXT
);

Insert some data into the Prepend table:

INSERT INTO Prepend VALUES
(1, '[1, 2, 3]', 0, 'Foo');

Use the PREPEND function to prepend the integer element to the list:

SELECT PREPEND(items, element) AS myprepend FROM Prepend;

Use the PREPEND function to prepend the text element to the list:

SELECT PREPEND(items, element2) AS myprepend FROM Prepend;

The PREPEND function requires a list as the first parameter. If you try to use it with a non-list value, an error will occur:

SELECT PREPEND(element, element2) AS myprepend FROM Prepend;

You can also use the PREPEND function when inserting data into a table. First, create a table named Foo with a column for the list:

CREATE TABLE Foo (
    elements LIST
);

Then, insert data into the Foo table using the PREPEND function:

INSERT INTO Foo VALUES (PREPEND(CAST('[1, 2, 3]' AS LIST), 0));

Finally, retrieve the list from the Foo table:

SELECT elements AS myprepend FROM Foo;