8/25/2023 0 Comments Postgresql vs sql liteBottom line for a given grouping field(item_id) any non-grouped values are just going to be picked out of hat and not really useful. Even if you resorted to as sub-query the avg_price and min_price would basically be some essentially random value. I know you said you didn't want aggregate functions but that is what you will have to do. So something like: SELECT item_id, min(avg_price), min(min_price) The ability to include bare columns in a query is an SQLite-specific extension. If you include a bare column in a query, other database engines will usually raise an error. Most other SQL database engines disallow bare columns. If an application overrides the built-in min() or max() aggregates with application-defined alternatives, then the values selected for bare columns will be taken from an arbitrary row. This special processing for min() or max() aggregates only works for the built-in implementation of those aggregates. The choice might be different for different bare columns within the same query. ![]() The choice of which min() or max() aggregate determines the selection of bare column values is arbitrary. If there are two or more min() or max() aggregates in the query, then bare column values will be taken from one of the rows on which one of the aggregates has their minimum or maximum value. There is no way to predict from which row the bare values will be choosen. If the same minimum or maximum value occurs on two or more rows, then bare values might be selected from any of those rows. There are limitations on this special behavior of min() and max(): So in the query above, the value of the "b" column in the output will be the value of the "b" column in the input row that has the largest "c" value. If there is exactly one min() or max() aggregate in the query, then all bare columns in the result set take values from an input row which also contains the minimum or maximum. Are you undertaking a strategic software development. ![]() SQLite stores the database in a single ordinary disk file that can be located anywhere in the directory. ![]() The SQLite library is less than 500kb while PostgreSQL is much larger in size. PostgreSQL supports almost everything that you can think of. A functional dependency exists if the grouped columns (or a subset thereof) are the primary key of the table containing the ungrouped column. MySQL vs PostgreSQL vs SQLite: A comparison between 3 popular relational database management systems. SQLite supports only five types: BLOB, NULL, INTEGER, TEXT, REAL. When GROUP BY is present, or any aggregate functions are present, it is not valid for the SELECT list expressions to refer to ungrouped columns except within aggregate functions or when the ungrouped column is functionally dependent on the grouped columns, since there would otherwise be more than one possible value to return for an ungrouped column.
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