subquery in A Sentence

    1

    Subqueries appearing in FROM can be preceded by the key word LATERAL.

    0
    2

    Also it is commonly used when value comparison in subqueries is required.

    0
    3

    IN is slower as it collects all results from the Subquery and processes it.

    0
    4

    More interesting cases, which can't be reduced to a plain join, arise when the Subquery involves grouping or aggregation.

    0
    5

    In this case all the Subquery rows must yield arrays of identical dimensionality, else the result would not be rectangular.

    0
    6

    When running IN, it collects all results from the Subquery and presents them for further processing, and this process takes a while.

    0
    7

    If the Subquery's output column is of an array type, the result will be an array of the same type but one higher dimension;

    0
    8

    When an aggregate expression appears in a Subquery(see Section 4.2.9 and Section 9.16), the aggregate is normally evaluated over the rows of the Subquery.

    0
    9

    I need to get the record with the MAX id from this joined table, but I only need the top row to be joined with the main query on this Subquery.

    0