General MySQL Oracle SQL Server

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Define an Anonymous Block in Oracle
How To Define an Anonymous Block in Oracle? An anonymous block must have an execution part, which is a group of other PL/SQL statements enclosed in the BEGIN ... END statement. Here is a script on how to define a simple anonymous block with SQL*Plus: SQL&gt; set serveroutput on; SQL&gt; begi... 2018-10-30, 2539🔥, 0💬

What Is a Dead Lock in MySQL
What Is a Dead Lock in MySQL? A dead lock is phenomenon happens between two transactions with each of them holding a lock that blocks the other transaction as shown in the following diagram: (transaction 1) (transaction 2) update row X to create lock 1 update row Y to create lock 2 update row X (blo... 2017-04-28, 2538🔥, 0💬

Privilege to Query Tables in Another Schema in Oracle
What Privilege Is Needed for a User to Query Tables in Another Schema in Oracle? For a user to run queries (SELECT statements) on tables of someone else's schema, he/she needs the SELECT ANY TABLE privilege. The following tutorial exercise gives you a good example of granting "dev" to query tables i... 2019-06-11, 2536🔥, 0💬

Open and Close an Explicit Cursor in Oracle
How To Open and Close an Explicit Cursor in Oracle? An existing cursor can be opened or closed by the OPEN or CLOSE statement as shown in the following sample script: DECLARE CURSOR c_list IS SELECT * FROM countries; CURSOR t_list IS SELECT * FROM employees WHERE employee_id = 100; BEGIN OPEN c_list... 2018-07-22, 2536🔥, 0💬

Show All Tables in a Database in MySQL
How To Get a List of All Tables in a Database in MySQL? If you want to see the table you have just created, you can use the "SHOW TABLES" command to get a list of all tables in database. The tutorial script gives you a good example: mysql&gt; SHOW TABLES; +---------------+ | Tables_in_fyi | +---... 2018-03-10, 2536🔥, 0💬

Getting Help Information from the Server in MySQL
How To Get Help Information from the Server in MySQL? While you are at the "mysql&gt;" prompt, you can get help information from the server by using the "HELP" command. The tutorial exercise below shows sevearal examples: &gt;cd \mysql\bin &gt;mysql -u root mysql&gt; HELP; ... List o... 2018-02-08, 2536🔥, 0💬

Recycle Bin - Storage to Hold Dropped Tables in Oracle
What Is Recycle Bin in Oracle? Recycle bin is a logical storage to hold the tables that have been dropped from the database, in case it was dropped in error. Tables in recycle bin can be recovered back into database by the Flashback Drop action. Oracle database recycle save the same purpose as the r... 2019-05-14, 2535🔥, 0💬

Managing Oracle Table Indexes
Where to find answers to frequently asked questions on Managing Oracle Table Indexes? Here is a list of frequently asked questions and their answers compiled by FYIcenter.com DBA team on Managing Oracle Table Indexes. The clear answers and sample scripts provided can be used as learning tutorials or... 2019-05-10, 2535🔥, 0💬

What Is View in MySQL
What Is View in MySQL? A view is a logical table defined by a query statement.   ⇒ What Is Join in MySQL ⇐ What Is Index in MySQL ⇑ Database Basics and Terminologies in MySQL ⇑⇑ MySQL Database Tutorials 2017-07-07, 2535🔥, 0💬

CREATE INDEX - Impact on Other User Sessions in SQL Server
What Is the Impact on Other User Sessions When Creating Indexes in SQL Server? If you are creating a new index on a table with existing data, all existing rows will be indexed as part of the CREATE INDEX statement. If the table is large, the indexing process could take some time. The impact of this ... 2016-11-08, 2534🔥, 0💬

Order of Columns in the SET Clause in MySQL
Is the Order of Columns in the SET Clause Important in MySQL? Yes. The order of columns in the SET clause of the UPDATE statement is important. There is a BIG DIFFERENCE between MySQL and Oracle on update columns with previous values: Oracle provides you the existing values from the database on colu... 2018-01-13, 2533🔥, 0💬

Data File for InnoDB Storage Engine in MySQL
Where Table Data Is Stored by the InnoDB Storage Engine in MySQL? By default, MySQL provides \mysql\data directory for all storage engines to store table data. Under \mysql\data directory, InnoDB storage engine will create 3 files to store and manage all tables that use the InnoDB storage engine: ib... 2017-08-13, 2533🔥, 0💬

Left Outer Join with the WHERE Clause in Oracle
How To Write a Left Outer Join with the WHERE Clause in Oracle? If you don't want to use the LEFT OUTER JOIN ... ON clause to write a left outer join, you can use a special criteria in the WHERE clause as "left_table.column = right_table.column(+)". The select statement below is an example of a left... 2019-10-18, 2532🔥, 0💬

What Is a SELECT Query Statement in SQL Server
What Is a SELECT Query Statement in SQL Server? The SELECT statement is also called the query statement. It is the most frequently used SQL statement in any database application. SELECT statements allows you to retrieve data from one or more tables or views, with different selection criteria, groupi... 2016-10-26, 2532🔥, 0💬

in Oracle
How To Delete All Rows from a Table in Oracle? 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 shows you a good exa... 2020-01-04, 2531🔥, 0💬

Drop an Existing Table in Oracle
How To Drop an Existing Table in Oracle? If you want to delete an existing table and its data rows, you can use the DROP TABLE statement as shown in this script: SQL&gt; connect HR/fyicenter Connected. SQL&gt; CREATE TABLE emp_dept_10 2 AS SELECT * FROM employees WHERE department_id=10; Tabl... 2019-05-25, 2529🔥, 0💬

Creating New Tables with SELECT Statements in MySQL
How To Create a New Table by Selecting Rows from Another Table in MySQL? Let's say you have a table with many data rows, now you want to create a backup copy of this table of all rows or a subset of them, you can use the "CREATE TABLE ... SELECT" statement. The tutorial script below gives you a good... 2018-03-04, 2529🔥, 0💬

Update Column Values on Multiple Rows in MySQL
How To Update Column Values on Multiple Rows in MySQL? If the WHERE clause in an UPDATE 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: mysql&gt; UPDATE fyi_lin... 2018-01-13, 2529🔥, 0💬

"CREATE VIEW/PROCEDURE" Statements - Creating a View and a Stored Procedure in SQL Server
How to create a view and a stored procedure using "CREATE VIEW/PROCEDURE" statements in SQL Server? This is the third tutorial of a quick lesson on creating login and configure users for databases with Transact-SQL statements. Granting a user access to a database involves three steps. First, you cre... 2016-11-27, 2529🔥, 0💬

Using ORDER BY with UNION Operators in SQL Server
How To Use ORDER BY with UNION Operators in SQL Server? If you need to sort the output from two queries grouped together with a UNION operator, you need to apply the ORDER BY clause at the group level, not at the subquery level. Note that SQL Server and MySQL react differently to the ORDER BY clause... 2016-10-26, 2529🔥, 0💬

Example of Passing Parameters to Procedures in Oracle
How To Pass Parameters to Procedures in Oracle? Store procedures or functions can take parameters. You need to define parameters while defining the procedure, and providing values to parameters while calling the procedure. The script below shows you how to do this: SQL&gt; CREATE OR REPLACE PROC... 2019-03-08, 2528🔥, 0💬

Renaming an Existing Column with Management Studio in SQL Server
How to rename an existing column with SQL Server Management Studio in SQL Server? If you are using SQL Server Management Studio, you can rename almost any data objects through the Object Explorer window. The tutorial example below shows you how to rename a column: 1. Run SQL Server Management Studio... 2016-11-15, 2528🔥, 0💬

Understanding and Managing Views in SQL Server
Where to find answers to frequently asked questions on Understanding and Managing Views in SQL Server? Here is a list of frequently asked questions and their answers compiled by FYIcenter.com DBA team on Understanding and Managing Views in SQL Server. Clear answers are provided with tutorial exercis... 2016-11-08, 2528🔥, 0💬

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, 2528🔥, 0💬

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General MySQL Oracle SQL Server