General MySQL Oracle SQL Server

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Importance of Column Order in the SET Clause in Update Statements in SQL Server
Is the Order of Columns in the SET Clause Important in SQL Server? The answer is NO. The order of columns in the SET clause of the UPDATE statement is NOT important. You probably already noticed from the previous tutorial. There is a BIG DIFFERENCE among SQL Server, MySQL and Oracle on update multip... 2016-11-02, 502👍, 0💬

Inserting Multiple Rows with One INSERT Statement in SQL Server
How To Insert Multiple Rows with One INSERT Statement in SQL Server? If you want to insert multiple rows with a single INSERT statement, you can use a subquery instead of the VALUES clause. Rows returned from the subquery will be inserted the target table. The following tutorial exercise gives you a... 2016-11-02, 502👍, 0💬

Updating Values with UPDATE Statements in SQL Server
How To Update Values in a Table with UPDATE Statements in SQL Server? If you want to update some values in one row or multiple rows in a table, you can use the UPDATE statement. The tutorial script below shows a good example: SELECT * FROM fyi_links WHERE id = 101 GO id url notes counts created 101 ... 2016-11-02, 500👍, 0💬

UPDATE Subquery Returning No Rows in SQL Server
What Happens If the UPDATE Subquery Returns No Rows in SQL Server? If you use a subquery to assign new values in the SET clause in an UPDATE statement, and the subquery returns no rows for an outer row, SQL Server will provide a NULL value to the SET clause. The tutorial exercise below shows you a g... 2016-11-02, 479👍, 0💬

Using Old Values to Define New Values in UPDATE Statements in SQL Server
How to use old values to define new values in UPDATE statements in SQL Server? If a row matches the WHERE clause in a UPDATE statement, existing values in this row can be used in expressions to provide new values in the SET clause. Existing values are represented by column names in the expressions. ... 2016-11-02, 462👍, 0💬

Using Values from Other Tables in UPDATE Statements in SQL Server
How To Use Values from Other Tables in UPDATE Statements in SQL Server? If you want to update values in one table with values from another table, you can use a subquery as an expression in the SET clause. The subquery should return only one row for each row in the update table that matches the WHERE... 2016-11-02, 462👍, 0💬

Providing Column Names in INSERT Statements in SQL Server
How to provide column names in INSERT Statements in SQL Server? If you don't want to specify values for columns that have default values, or you want to specify values to columns in an order different than how they are defined, you can provide a column list in the INSERT statement. If a column is om... 2016-11-02, 444👍, 0💬

Updating Multiple Rows with One UPDATE Statement in SQL Server
How To Update Multiple Rows with One UPDATE Statement in SQL Server? If the WHERE clause in an UPDATE statement matches multiple rows, the SET clause will be applied to all matched rows. This rule allows you to update values on multiple rows in a single UPDATE statement. Here is a good example: SELE... 2016-11-02, 395👍, 0💬

"RIGHT OUTER JOIN ... ON" - Writing Queries with Right Outer Joins in SQL Server
How To Write a Query with a Right Outer Join in SQL Server? 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 two tables: fyi_links and fyi_rates. The join c... 2016-10-30, 755👍, 0💬

"INNER JOIN ... ON" - Writing Queries with Inner Joins in SQL Server
How To Write a Query with an Inner Join in SQL Server? If you want to query from two tables with an inner join, you can use the INNER JOIN ... ON clause in the FROM clause. The tutorial exercise below creates another testing table and returns output with an inner join from two tables: fyi_links and ... 2016-10-30, 723👍, 0💬

"LEFT OUTER JOIN ... ON" - Writing Queries with Left Outer Joins in SQL Server
How To Write a Query with a Left Outer Join in SQL Server? If you want to query from two tables with a left outer join, you can use the LEFT OUTER JOIN ... ON clause in the FROM clause. The following query returns output with a left outer join from two tables: fyi_links and fyi_rates. The join condi... 2016-10-30, 690👍, 0💬

Defining and Using Table Alias Names in SQL Server
How To Define and Use Table Alias Names in SQL Server? When column names need to be prefixed with table names, you can define table alias name and use them to prefix column names. To define an alias for a table name, just enter the alias name right after the original table name in the FROM clause as... 2016-10-30, 553👍, 0💬

Deleting All Rows with TRUNCATE TABLE Statement in SQL Server
How To Delete All Rows with TRUNCATE TABLE Statement in SQL Server? If you want to delete all rows from a table, you have two options: Use the DELETE statement with no WHERE clause. Use the TRUNCATE TABLE statement. The TRUNCATE statement is more efficient the DELETE statement. The tutorial exercise... 2016-10-30, 532👍, 0💬

Joining Two Tables in a Single Query in SQL Server
How To Join Two Tables in a Single Query in SQL Server? Two tables can be joined together in a query in 4 ways: Inner Join: Returns only rows from both tables that satisfy the join condition. Left Outer Join: Returns rows from both tables that satisfy the join condition, and the rest of rows from th... 2016-10-30, 512👍, 0💬

Using SELECT Statements with Joins and Subqueries in SQL Server
Where to find answers to frequently asked questions on Using SELECT Statements with Joins and Subqueries in SQL Server? Here is a list of frequently asked questions and their answers compiled by FYIcenter.com DBA team on Using SELECT Statements with Joins and Subqueries in SQL Server. Clear answers ... 2016-10-30, 510👍, 0💬

Deleting All Rows with DELETE Statements in SQL Server
How To Delete All Rows with DELETE Statements in SQL Server? If you want to delete all rows from a table, you have two options: Use the DELETE statement with no WHERE clause. Use the TRUNCATE TABLE statement. Here is an example of deleting all rows with a DELETE statement: SELECT COUNT(*) FROM fyi_l... 2016-10-30, 500👍, 0💬

Deleting an Existing Row with DELETE Statements in SQL Server
How To Delete an Existing Row with DELETE Statements in SQL Server? If you want to delete an existing row from a table, you can use the DELETE statement with a WHERE clause to identify that row. Here is good sample of DELETE statements: -- insert a row for this test INSERT INTO fyi_links (url, id) V... 2016-10-30, 496👍, 0💬

Deleting Multiple Rows with One DELETE Statement in SQL Server
How To Delete Multiple Rows with One DELETE Statement in SQL Server? You can delete multiple rows from a table in the same way as deleting a single row, except that the WHERE clause will match multiple rows. The tutorial exercise below deletes 3 rows from the fyi_links table: -- view rows to be dele... 2016-10-30, 487👍, 0💬

"FULL OUTER JOIN ... ON" - Writing Queries with Full Outer Joins in SQL Server
How To Write a Query with a Full Outer Join in SQL Server? If you want to query from two tables with a full outer join, you can use the FULL OUTER JOIN ... ON clause in the FROM clause. The following query returns output with a full outer join from two tables: fyi_links and fyi_rates. The join condi... 2016-10-29, 709👍, 0💬

Using Subqueries with the EXISTS Operators in SQL Server
How To Use Subqueries with the EXISTS Operators in SQL Server? 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 (subquery)". It returns rows from fyi_links table t... 2016-10-29, 576👍, 0💬

Using Subqueries in the FROM Clause in SQL Server
How To Use Subqueries in the FROM Clause in SQL Server? 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 used in this way become a temporary table, and yo... 2016-10-29, 534👍, 0💬

Returning the Second 5 Rows from a Query in SQL Server
How To Return the Second 5 Rows in SQL Server? If you want to display query output in multiple pages with 5 rows per page, and the visitor wants to see the output for the second page, you need to display query output from row 6 to row 10. If you are using MySQL server, you can use the "LIMIT startRo... 2016-10-29, 524👍, 0💬

Counting Groups Returned with the GROUP BY Clause in SQL Server
How To Count Groups Returned with the GROUP BY Clause in SQL Server? 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 number of groups, you can put the GROUP BY query i... 2016-10-29, 515👍, 0💬

Writing Inner Joins with the WHERE Clause in SQL Server
How To Write an Inner Join with the WHERE Clause in SQL Server? 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: SELECT l.id, l.url, r.comment FROM fyi_links l, fyi_rates r WHERE ... 2016-10-29, 498👍, 0💬

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General MySQL Oracle SQL Server