database - How to select unique records by SQL - Stack Overflow
DISTINCT keyword is supposed to be applied to all the columns in the select query and not just to the column next to which DISTINCT keyword is written. So, basically, it means that every row returned in the result will be unique in terms of the combination of the select query columns. In OP's question, the below two result rows are already ...
What does "DISTINCT ON (expression)" do? - Stack Overflow
2017年10月4日 · The DISTINCT ON expression(s) must match the leftmost ORDER BY expression(s). The first point is that whatever you put in the ON (), must come first in the the ORDER BY, for reasons that will hopefully shortly become clear... SELECT DISTINCT ON (a) a, b, c FROM a_table ORDER BY a, b
Get unique values using STRING_AGG in SQL Server
2018年5月29日 · Use the DISTINCT keyword in a subquery to remove duplicates before combining the results: SQL Fiddle. SELECT ProjectID ,STRING_AGG(value, ',') WITHIN GROUP (ORDER BY value) AS NewField FROM ( SELECT DISTINCT ProjectID , newId.value FROM [dbo].[Data] WITH (NOLOCK) CROSS APPLY STRING_SPLIT([bID],';') AS newId WHERE …
sql - Make a query with DISTINCT clause run faster - Stack Overflow
2016年3月3日 · select distinct type, account from balances_tbl where month = 'DEC-12' The table balances_tbl has over 3 million records per month. The distinct type and account rows are maybe around 20,000 records. The month column is indexed. The type and account columns are also indexed. The query takes a really long time (about 30 minutes) to execute.
How do I (or can I) SELECT DISTINCT on multiple columns?
2008年9月10日 · UPDATE sales s SET status = 'ACTIVE' WHERE NOT EXISTS ( SELECT FROM sales s1 -- SELECT list can be empty for EXISTS WHERE s.saleprice = s1.saleprice AND s.saledate = s1.saledate AND s.id <> s1.id -- except for row itself ) AND s.status IS DISTINCT FROM 'ACTIVE'; -- avoid empty updates. see below
MySQL: Select DISTINCT / UNIQUE, but return all columns?
2011年5月25日 · WITH c AS (SELECT DISTINCT a, b, c FROM tableName) SELECT * FROM tableName r, c WHERE c.rowid=r.rowid AND c.a=r.a AND c.b=r.b AND c.c=r.c This also allows you to select only the rows selected in the WITH clauses query.
sql - Alternative to DISTINCT Function - Stack Overflow
2013年10月24日 · SELECT DISTINCT Table1.Col1, Table2.Col1, Table1.Col3 FROM Table1 INNER JOIN Table2 ON Table1.FK = Table2.ID WHERE Table1.Foo = 1865 AND Table2.Type = 1 sql t-sql
Using DISTINCT along with GROUP BY in SQL Server
select distinct col1, percentile_cont(col2) within group (order by col2) over (partition by col1), percentile_cont(col2) within group (order by col2) over (partition by col1, col3), from tablea You would use this to return different levels of aggregation returned in a single row.
group by - Distinct pair of values SQL - Stack Overflow
Consider create table pairs ( number a, number b ) Where the data is 1,1 1,1 1,1 2,4 2,4 3,2 3,2 5,1 Etc. What query gives me the distinct values the number column b has So I can see 1,1 ...
How to quickly select DISTINCT dates from a Date/Time field, SQL …
2016年12月9日 · The query select distinct date_only from foo will use this indexed view instead. Is still a scan technically, but on an already 'distinct' index, so only the needed records are scanned. Is still a scan technically, but on an already 'distinct' index, …