General MySQL Oracle SQL Server

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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, 2528🔥, 0💬

Primary Key - Default Indexes of Tables in SQL Server
Is the PRIMARY KEY Column of a Table an Index in SQL Server? If you define a primary key on a table, an index for the primary key column will be created by default. The tutorial exercise below shows you the index created as part of the primary key column of "fyi_links": USE FyiCenterData; GO -- Drop... 2016-11-13, 2528🔥, 0💬

Run the Anonymous Block Again in Oracle
How To Run the Anonymous Block Again in Oracle? If you have an anonymous block defined in your session, you can run it any time by using the "/" command as shown in the following script: SQL&gt; set serveroutput on; SQL&gt; begin 2 dbms_output.put_line('This is a PL/SQL FAQ.'); 3 end; 4 / Th... 2018-10-30, 2527🔥, 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, 2526🔥, 0💬

PHP ODBC - odbc_fetch_array() - Looping through Returning Rows
PHP ODBC - How To Loop through Returning Rows? The best way to query tables and loop through returning rows is to run a SELECT statement with the odbc_exec() function, catch the returning object as a result set, and loop through the result with odbc_fetch_array() function in a while loop as shown in... 2024-05-29, 2525🔥, 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, 2525🔥, 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, 2525🔥, 0💬

Syntaxes of Creating Table-Valued Functions in SQL Server
How Many Ways to Create Table-Valued Functions in SQL Server Transact-SQL? SQL Server supports two syntaxes of creating table-valued functions: 1. Inline Table-valued Functions - A table-valued function created with a single SELECT statement: CREATE FUNCTION function_name( @parameter_1 data_type, @p... 2016-12-18, 2524🔥, 0💬

Define the ID Column as Auto-Incremented in MySQL
How To Define the ID Column as Auto-Incremented in MySQL? Many tables require an ID column to assign a unique ID number for each row in the table. For example, if you have a table to hold forum member profiles, you need an ID number to identify each member. To allow MySQL server to automatically ass... 2017-09-12, 2522🔥, 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, 2521🔥, 0💬

Transaction Committed when DDL Statement Executed in MySQL
What Happens to the Current Transaction If a DDL Statement Is Executed in MySQL? If a DDL statement is executed, the current transaction will be committed and ended. All the database changes made in the current transaction will become permanent. This is called an implicit commit by a DDL statement. ... 2016-10-17, 2521🔥, 0💬

Getting a List of All Databases on the Server in SQL Server
How to get a list all databases on the SQL server in SQL Server? If you don't remember database names you have created, you can get a list of all databases on the server by query the "sys.databases" view as shown in this tutorial example: CREATE DATABASE FyiCenterData GO SELECT name, database_id, cr... 2016-11-24, 2520🔥, 0💬

Create a Test Table for DML Testing in Oracle
How To Create a Testing Table in Oracle? If you want to practice DML statements, you should create a testing table as shown in the script below: CREATE TABLE fyi_links (id NUMBER(4) PRIMARY KEY, url VARCHAR2(80) NOT NULL, notes VARCHAR2(1024), counts NUMBER, created DATE DEFAULT (sysdate)); Table cr... 2020-02-07, 2519🔥, 0💬

Loop through the Implicit Cursor in Oracle
How To Loop through Data Rows in the Implicit Curosr in Oracle? You use the FOR ... IN ... LOOP statement to loop through data rows in the implicit cursor as the following syntax: FOR row IN dml_statement LOOP (statement block with row.field) END LOOP; Here "row" is a local RECORD type variable with... 2018-07-22, 2518🔥, 0💬

Starting SQL Server Browser Service
How To Start SQL Server Browser Service? SQL Server Browser Service is installed as part of the SQL Server. But it is turned off by default to reduce the security risk. If you want start SQL Server Browser Service to allow the SQL Server to accept network connections, you need to follow the steps be... 2024-07-25, 2516🔥, 0💬

Ways to Create an Oracle Database in Oracle
How To Create an Oracle Database in Oracle? There are two ways to create a new database: Use the Database Configuration Assistant (DBCA) to create a database interactively. Use the CREATE DATABASE statement to create a database manually.   ⇒ Create an Oracle Database Manually in Oracle ⇐ Creating N... 2019-04-09, 2516🔥, 0💬

Creating Stored Procedures with Parameters in SQL Server
How To Create Stored Procedures with Parameters in SQL Server Transact-SQL? Very often, you need to create a stored procedure with one or more parameters. You only supply values to those parameters at the time of executing the stored procedure. Stored procedures with parameters can be created with t... 2017-01-05, 2516🔥, 0💬

System Defined User Roles in Oracle
What Are the System Predefined User Roles in Oracle? Oracle 10g XE comes with 3 predefined roles: CONNECT - Enables a user to connect to the database. Grant this role to any user or application that needs database access. RESOURCE - Enables a user to create certain types of schema objects in his own... 2019-07-30, 2515🔥, 0💬

Query with a Full Outer Join in MySQL
How To Write a Query with a Full Outer Join in MySQL? There is no way to do full outer join in MySQL. It does not support this feature at the current MySQL release.   ⇒ Inner Join with the WHERE Clause in MySQL ⇐ Query with a Right Outer Join in MySQL ⇑ SELECT Statements with JOIN and Subqueries in... 2017-09-28, 2515🔥, 0💬

Count Duplicated Values in a Column in Oracle
How To Count Duplicated Values in a Column in Oracle? If you have a column with duplicated values, and you want to know what are those duplicated values are and how many duplicates are there for each of those values, you can use the GROUP BY ... HAVING clause as shown in the following example. It re... 2019-11-21, 2514🔥, 0💬

Define an Explicit Cursor in Oracle
How To Define an Explicit Cursor in Oracle? An explicit cursor must be defined in the declaration part of a procedure or function with the CURSOR ... IS statement as shown in the following sample script: DECLARE CURSOR c_list IS SELECT * FROM countries; CURSOR t_list IS SELECT * FROM employees WHERE... 2018-07-22, 2514🔥, 0💬

Performing Comparison on Floating Point Numbers in SQL Server
How To Perform Comparison on Floating Point Numbers in SQL Server Transact-SQL? Comparison operations on approximate (floating point) numbers are also easy to understand. Just watch out rounding operations performed during conversions. Here are two examples of floating point number comparisons: -- R... 2017-01-21, 2514🔥, 0💬

Data Types Supported in PL/SQL in Oracle
How Many Data Types Are Supported in Oracle? PL/SQL supports two groups of data types: SQL Data Types - All data types used for table columns. PL/SQL Special Data Types - Like BOOLEAN or PLS_INTEGER. The script below shows some data type examples: SQL&gt; set serveroutput on; SQL&gt; DECLARE... 2019-03-20, 2512🔥, 0💬

What Is Oracle SQL Developer in Oracle
What Is Oracle SQL Developer in Oracle? Oracle SQL Developer is a new, free graphical tool that enhances productivity and simplifies database development tasks. With SQL Developer, you can browse database objects, run SQL statements and SQL scripts, and edit and debug PL/SQL statements. You can also... 2019-02-18, 2512🔥, 0💬

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General MySQL Oracle SQL Server