General MySQL Oracle SQL Server

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Use "mysql" to Run SQL Statements in MySQL
How To Use "mysql" to Run SQL Statements in MySQL? If you want to run SQL statement to your server with "mysql", you need to start "mysql" and enter your SQL statement at the "mysql" prompt. Here is a good tutorial exercise that shows you how to run two SQL statements with "mysql": &gt;cd \mysql... 2018-02-28, 2377🔥, 0💬

Ways to Join Two Tables in a Single Query in Oracle
How To Join Two Tables in a Single Query in Oracle? 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 the fi... 2019-10-27, 2375🔥, 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, 2374🔥, 0💬

Rollback the Current Transaction in MySQL
How To Rollback the Current Transaction in MySQL? If you have used some DML statements updated some data objects, you find a problem with those updates, and you don't want those updates to be permanently recorded in the database, you can use the ROLLBACK command. It will remove all the database chan... 2016-10-17, 2374🔥, 0💬

Omit Columns in INSERT Statements in Oracle
How To Omit Columns with Default Values in INSERT Statement in Oracle? 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 colum... 2020-01-29, 2373🔥, 0💬

What Is a Table in SQL Server
What is a table in SQL Server? A table in database is a data object used to store data. Tables have the following features: Data is stored in a table with a structure of rows and columns. Columns must be pre-defined with names, types and constrains. A table object may have other associated data obje... 2016-11-20, 2373🔥, 0💬

What Is "mysqlshow" Command in MySQL
What Is "mysqlshow" in MySQL? "mysqlshow" is a command-line interface for end users to see information on tables and columns. Here are some sample commands supported by "mysqlshow": "mysqlshow" - Shows all the databases. "mysqlshow databaseName" - Shows all the tables in the specified database. "mys... 2018-02-28, 2372🔥, 0💬

"IS NULL" - Testing NULL Values in SQL Server
How To Test NULL Values Properly in SQL Server Transact-SQL? From previous tutorials, you learned that comparing expressions with NULL will always result NULL. So you can not use comparison operators to test if an expression represents a NULL value or not. To test expressions for NULL values, you sh... 2017-02-03, 2372🔥, 0💬

Using SELECT Statements and GROUP BY Clauses in SQL Server
Where to find answers to frequently asked questions on Using SELECT Statements and GROUP BY Clauses in SQL Server? Here is a list of frequently asked questions and their answers compiled by FYIcenter.com DBA team on Using SELECT Statements and GROUP BY Clauses in SQL Server. Clear answers are provid... 2016-10-26, 2372🔥, 0💬

Add Another Datafile to a Tablespace in Oracle
How To Add Another Datafile to a Tablespace in Oracle? If you created a tablespace with a data file a month ago, now 80% of the data file is used, you should add another data file to the tablespace. This can be done by using the ALTER TABLESPACE ... ADD DATAFILE statement. See the following sample s... 2019-04-09, 2370🔥, 0💬

What Is Row in MySQL
What Is Row in MySQL? A row is a unit of data with related data items stored as one item in one column in a table.   ⇒ What Is Primary key in MySQL ⇐ What Is Column in MySQL ⇑ Database Basics and Terminologies in MySQL ⇑⇑ MySQL Database Tutorials 2017-07-15, 2368🔥, 0💬

Violation of Unique Value Constraint in MySQL
What Happens If Unique Value Constraints Are Violated in MySQL? If you are inserting a new record that has values violating a unique constraint, you will get an error. Note that primary key column has a unique value constraint by default. The following tutorial exercise gives you some good examples:... 2018-01-16, 2367🔥, 0💬

Sort Query Output in Descending Order in Oracle
How To Sort Query Output in Descending Order in Oracle? If you want to sort a column in descending order, you can specify the DESC keyword in the ORDER BY clause. The following SELECT statement first sorts the department in descending order, then sorts the salary in ascending order: SQL&gt; SELE... 2019-12-19, 2366🔥, 0💬

Character String Data Types in MySQL
What Are Character String Data Types in MySQL? MySQL supports the following string data types: CHAR(n) same as CHARACTER(n) - Fixed width and " " padded characters strings. Default character set is ASCII. NCHAR(n) same as NATIONAL CHARACTER(n) - Fixed width and " " padded character strings with UTF8... 2018-04-12, 2366🔥, 0💬

Retrieving the Last Sequence ID in MySQL
How To Get the Last ID Assigned by MySQL in MySQL? If you use an ID column with AUTO_INCREMENT attribute, you can use the mysql_insert_id() function to get the last ID value assigned by the MySQL server, as shown in the sample script below: &lt;?php include "mysql_connection.php"; $sql = "INSERT... 2017-09-12, 2366🔥, 0💬

Creating a View with Data from Another View in SQL Server
Can You Create a View using Data from Another View in SQL Server? Can You Create a View with Data from Another View? The answer is yes. A view can be used as a table to build other views. The tutorial exercise below shows you how to create a view using data from another view: USE AdventureWorksLT; G... 2016-11-05, 2366🔥, 0💬

PHP ODBC - Including Date and Time Values in SQL Statements
PHP ODBC - How To Include Date and Time Values in SQL Statements? If you want to provide date and time values in a SQL statement, you should write them in the format of "yyyy-mm-dd hh:mm:ss", and quoted with single quotes ('). The tutorial exercise below shows you two INSERT statements. The first on... 2024-05-05, 2364🔥, 0💬

LAST_INSERT_ID() - Last Value of AUTO_INCREMENT Column
How to obtain the last inserted value of an AUTO_INCREMENT column using the LAST_INSERT_ID() function? LAST_INSERT_ID() is a MySQL built-in function that returns the last inserted value of an AUTO_INCREMENT column. For example: CREATE TABLE MyTable (id INTEGER AUTO_INCREMENT, comment CHAR(80), PRIMA... 2025-04-11, 2363🔥, 0💬

Use Group Functions in ORDER BY Clause in Oracle
Can Group Functions Be Used in the ORDER BY Clause in Oracle? If the query output is aggregated as groups, you can sort the groups by using group functions in the ORDER BY clause. The following statement returns how many employees are having the same salary in each department. The group output is so... 2019-10-27, 2363🔥, 0💬

Commit the Current Transaction in Oracle
How To Commit the Current Transaction in Oracle? If you have used some DML statements updated some data objects, and you want to have the updates to be permanently recorded in the database, you can use the COMMIT statement. It will make all the database changes made in the current transaction become... 2019-09-04, 2363🔥, 0💬

Supported Transaction Isolation Levels in Oracle
What Are Transaction Isolation Levels Supported by Oracle in Oracle? Oracle supports two transaction isolation levels: READ COMMITTED (the default option). If the transaction contains DML that requires row locks held by another transaction, then the DML statement waits until the row locks are releas... 2019-08-19, 2362🔥, 0💬

"CREATE TRIGGER" - Creating a DDL Trigger in SQL Server
How To Create a DDL Trigger using "CREATE TRIGGER" Statements in SQL Server? A DDL trigger is defined to handle a DDL statement event, like create, alter and drop tables, views, indexes, etc. DDL triggers can be used to generate warning messages on database object changes. The format of creating a D... 2016-10-22, 2362🔥, 0💬

Select All Columns of All Rows in Oracle
How To Select All Columns of All Rows from a Table in Oracle? The simplest query statement is the one that selects all columns of all rows from a table: "SELECT * FROM table_name;". The (*) in the SELECT clause tells the query to return all columns. The tutorial exercise below gives you a good examp... 2019-12-19, 2361🔥, 0💬

Create an Index for a Given Table in MySQL
How To Create an Index for a Given Table in MySQL? If you have a table with a lots of rows, and you know that one of the columns will be used often as a search criteria, you can add an index for that column to improve the search performance. To add an index, you can use the "CREATE INDEX" statement ... 2018-02-14, 2361🔥, 0💬

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General MySQL Oracle SQL Server