DISTINCT works to select a distinct combination of all the columns you selected. In this case, the combination "item1,data1" and "item1,data2" are two completely different combinations of the two …

Aug 11, 2017 · DISTINCT A instrução SELECT DISTINCT é usada para retornar apenas valores distintos (diferentes). Dentro de uma tabela, uma coluna geralmente contém muitos valores …

Sep 10, 2008 · The problem with your query is that when using a GROUP BY clause (which you essentially do by using distinct) you can only use columns that you group by or aggregate functions.

Jul 25, 2018 · select distinct * uses the tuple of all columns to determine distinctness. It's the same as select distinct col1, col2, .. for all columns in the table: the resulting columns returned will also be …

Apr 5, 2019 · SELECT COUNT(DISTINCT column_name) AS some_alias FROM table_name This will count only the distinct values for that column.

Dec 3, 2008 · Use SELECT DISTINCT because this is standard SQL, and SELECT UNIQUE is non-standard, and in database brands other than Oracle, SELECT UNIQUE may not be recognized at all.

DISTINCT is a modifier for the query itself, i.e. you don't select a distinct column, you make a SELECT DISTINCT query. In other words: DISTINCT tells the server to go through the whole result set and …

Feb 19, 2017 · SELECT DISTINCT TOP 1 ID, Email, ProductName, ProductModel FROM Products ORDER BY ID DESC The TOP 1 will return only the first record, by ordering it by the ID descending …

Oct 4, 2017 · SELECT DISTINCT ON (a) a, b, c FROM a_table ORDER BY a, b The results are then filtered, so that for each of the distinct entities, only the first row is actually returned.

Sep 25, 2019 · SQL - SELECT DISTINCT em apenas um campo Perguntada 6 anos, 3 meses atrás Modified 6 anos, 3 meses atrás Vista 8mil vezes