SELECT DISTINCT ... means that at the end of the query evaluation, rows that are complete duplicates of another row (in all columns) are removed. So SELECT DISTINCT COUNT(userid) FROM SomeTable will first count the number of rows where userid is not NULL, yielding a single row as resul...
I'm not sure why my SELECT statement with DISTINCT still shows duplicate. Any suggestion is appreciated. Thank you. SQL Server SQL Server A family of Microsoft relational database management and analysis systems for e-commerce, line-of-business, and data warehousing solutions. 13,507 questions...
SELECT [ALL | DISTINCT | DISTINCTROW | [TOPn[PERCENT]]] FROMtable A SELECT statement containing these predicates has the following parts:
SQL SELECT DISTINCT 语句 SELECT DISTINCT 语句用于返回唯一不同的值。 SQL SELECT DISTINCT 语句 在表中,一个列可能会包含多个重复值,有时您也许希望仅仅列出不同(distinct)的值。 DISTINCT 关键词用于返回唯一不同的值。 SQL SELECT DISTINCT 语法 SELECT DISTINCT column_name,column_name FROM table_name; 在本...
SELECT Example Without DISTINCT If you omit theDISTINCTkeyword, the SQL statement returns the "Country" value from all the records of the "Customers" table: Example SELECTCountryFROMCustomers; Try it Yourself » Count Distinct By using theDISTINCTkeyword in a function calledCOUNT, we can return...
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The SELECT DISTINCT statement is used to return only distinct (different) values.The SQL SELECT DISTINCT StatementIn a table, a column may contain many duplicate values; and sometimes you only want to list the different (distinct) values.
(SELECT INDEX_NAME FROM T3 WHERE T3.TABLESPACE_NAME= T2.TABLESPACE_NAME); 311 rows selected. Execution Plan --- 0 SELECT STATEMENT Optimizer=CHOOSE(Cost=12 Card=668 Bytes=62124) 1 0 HASH JOIN (SEMI) (Cost=12 Card=668 Bytes=62124) 2 1 HASHJOIN (Cost=9 Card=668 Bytes=39412) 3 ...
Could you please tell me what are the effects of using the DISTINCT keyword before a group of different column names in a SELECT statement? Recently, I created a query with DISTINCT in front of the first column in a list of three, and to my pleasant surprise, it had the effect of retu...
3 ( SELECT INDEX_NAME FROM T3 WHERET3.TABLESPACE_NAME = T2.TABLESPACE_NAME); 311 rows selected. Execution Plan --- 0 SELECT STATEMENT Optimizer=CHOOSE(Cost=16 Card=1 Bytes=93) 1 0 SORT (UNIQUE) (Cost=16 Card=1 Bytes=93) 2 1 HASH JOIN (Cost=12 Card=...