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10 kwi 2011 · How can I use the DISTINCT clause with WHERE? For example: SELECT * FROM table WHERE DISTINCT email; -- email is a column name I want to select all columns from a table with distinct email addres...
SELECT key, MIN(value) AS value FROM tableX GROUP BY key ; PostgreSQL has a special non-standard DISTINCT ON operator that can also be used. The optional ORDER BY is for selecting which row from every group should be selected:
16 mar 2016 · SELECT d.dept, d.role1, d.role2, DEF FROM @data d WHERE EXISTS ( SELECT 1 FROM @data WHERE dept = d.dept AND role1 = d.role1 AND role2 = d.role2 AND DEF <> d.DEF ); The subquery return 0 to n rows. If at least one row exists, the row from the main table is returned.
23 lut 2023 · As its name implies, the DISTINCT keyword is commonly used in a SQL SELECT statement to return a distinct set of values. This tip will look at several simple examples of using SELECT DISTINCT that you can copy, paste, and edit for your needs.
23 wrz 2023 · For example, to find unique values in the “name” column of a table called “employees,” you can write the following query: SELECT DISTINCT name FROM employees; 2. GROUP BY clause. Another effective method is to use the GROUP BY clause in combination with aggregate functions.
By using the DISTINCT keyword in a function called COUNT, we can return the number of different countries. Example SELECT COUNT(DISTINCT Country) FROM Customers;
5 kwi 2021 · Use DISTINCT and GROUP BY in the correct queries to obtain the required results. Summary. The DISTINCT clause be used with a list of columns to display all unique combinations of values stored in the table. In our PETS table, we noticed that we had two pet types and two pet genders.
