How To Name Query Output Columns

Q

How To Name Query Output Columns? - MySQL FAQs - SQL SELECT Statements with JOIN and Subqueries

✍: FYIcenter.com

A

Each column in the query output has a default name. If you don't like the default name, you can specify a new name for any column in the query output by using the AS clause. The following statement shows you a good example:

mysql> SELECT tag AS Category, YEAR(created) AS Year, 
   COUNT(*) AS Counts FROM fyi_links 
   GROUP BY tag, YEAR(created) ORDER BY COUNT(*) DESC;
+----------+------+--------+
| Category | Year | Counts |
+----------+------+--------+
| DBA      | 2006 |      2 |
| DEV      | 2006 |      1 |
| SQA      | 2006 |      1 |
| DBA      | 2005 |      1 |
| DEV      | 2004 |      1 |
| SQA      | 2003 |      1 |
+----------+------+--------+
6 rows in set (0.00 sec)

2007-05-11, 5269👍, 0💬

How To Use Subqueries in the FROM clause
How To Use Subqueries in the FROM clause? - MySQL FAQs - SQL SELECT Statements with JOIN and Subqueries If you have a query returning many rows of data, and you want to perform another query on those rows, you can put the first query as a subquery in the FROM clause of the second query. A subquery u... 2007-05-11, 7495👍, 0💬

How To Use Subqueries with the EXISTS Operator
How To Use Subqueries with the EXISTS Operator? - MySQL FAQs - SQL SELECT Statements with JOIN and Subqueries A subquery can be used with the EXISTS operator as "EXISTS (subquery)", which returns true if the subquery returns one or more rows. The following statement is a good example of "EXISTS (sub... 2007-05-11, 6020👍, 0💬

How To Count Groups Returned with the GROUP BY Clause
How To Count Groups Returned with the GROUP BY Clause? - MySQL FAQs - SQL SELECT Statements with JOIN and Subqueries If you use the COUNT(*) function on groups returned with the GROUP BY clause, it will count the number of rows within each group, not the number of groups. If you want to count the nu... 2007-05-11, 5898👍, 0💬

How To Write an Inner Join with the WHERE Clause
How To Write an Inner Join with the WHERE Clause? - MySQL FAQs - SQL SELECT Statements with JOIN and Subqueries If you don't want to use the INNER JOIN ... ON clause to write an inner join, you can put the join condition in the WHERE clause as shown in the following query example: mysql> SELECT l.id... 2007-05-11, 5497👍, 0💬

What Is a Subquery
What Is a Subquery? - MySQL FAQs - SQL SELECT Statements with JOIN and Subqueries A subquery is a SELECT statement used as part of the selection criteria of the main SELECT statement. The subquery specified in the WHERE clause will be evaluated repeated on each row of the selection base table. The o... 2007-05-11, 5410👍, 0💬

How To Name Query Output Columns
How To Name Query Output Columns? - MySQL FAQs - SQL SELECT Statements with JOIN and Subqueries Each column in the query output has a default name. If you don't like the default name, you can specify a new name for any column in the query output by using the AS clause. The following statement shows ... 2007-05-11, 5270👍, 0💬

How To Write a Query with a Full Outer Join
How To Write a Query with a Full Outer Join? - MySQL FAQs - SQL SELECT Statements with JOIN and Subqueries There is no way to do full outer join in MySQL. It does not support this feature at the current MySQL release. 2007-05-11, 5269👍, 0💬

How To Write a Query with a Right Outer Join
How To Write a Query with a Right Outer Join? - MySQL FAQs - SQL SELECT Statements with JOIN and Subqueries If you want to query from two tables with a right outer join, you can use the RIGHT OUTER JOIN ... ON clause in the FROM clause. The following query returns output with a right outer join from... 2007-05-11, 5233👍, 0💬

How To Define and Use Table Alias Names
How To Define and Use Table Alias Names? - MySQL FAQs - SQL SELECT Statements with JOIN and Subqueries When column names need to be prefixed with table names, you can define table alias name and use them to prefix column names as shown in the following select statement: mysql> SELECT l.id, l.url, r.... 2007-05-11, 5206👍, 0💬

All rights in the contents of this web site are reserved by the individual author. fyicenter.com does not guarantee the truthfulness, accuracy, or reliability of any contents.