Basic VALUES syntax in YQL
VALUES as a top-level operator
It lets you create a table from specified values. For example, this statement creates a table of k columns and n rows:
VALUES (expr_11, expr_12, ..., expr_1k),
(expr_21, expr_22, ..., expr_2k),
....
(expr_n1, expr_n2, ..., expr_nk);
This statement is totally equivalent to the following one:
SELECT expr_11, expr_12, ..., expr_1k UNION ALL
SELECT expr_21, expr_22, ..., expr_2k UNION ALL
....
SELECT expr_n1, expr_n2, ..., expr_nk;
Example
VALUES (1,2), (3,4);
VALUES after FROM
VALUES can also be used in a subquery, after FROM. For example, the following two queries are equivalent:
VALUES (1,2), (3,4);
SELECT * FROM (VALUES (1,2), (3,4));
In all the examples above, column names are assigned by YQL and have the format column0 ... columnN
. To assign arbitrary column names, you can use the following construct:
SELECT * FROM (VALUES (1,2), (3,4)) as t(x,y);
In this case, the columns will get the names x
, y
.