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Entering Characters as HEX Numbers in MySQL
How To Enter Characters as HEX Numbers in MySQL? If you want to enter characters as HEX numbers, you can quote HEX numbers with single quotes and a prefix of (X), or just prefix HEX numbers with (0x). A HEX number string will be automatically converted into a character string, if the expression cont...
2018-03-31, 356👍, 0💬

Converting Character Strings to Dates in MySQL
How To Convert Character Strings to Dates in MySQL? If you have a character string that represents a date, and you want to convert it into a date value, you can use the STR_TO_DATE(string, format) function. STR_TO_DATE() shares the same formatting codes with DATE_FORMAT() function. The tutorial exer...
2017-12-26, 356👍, 0💬

Merge Outputs from Two Queries in MySQL
How To Use UNION to Merge Outputs from Two Queries Together in MySQL? If you have two queries that returns the same row fields, you can merge their outputs together with the UNION operator. The following tutorial exercise shows you how to return all links that were created since year 2006 plus the o...
2017-12-21, 356👍, 0💬

Using Cursors in SQL Server Transact-SQL
Where to find answers to frequently asked questions on Using Cursors in SQL Server Transact-SQL? I want to loop through rows in a result set. Here is a list of frequently asked questions and their answers compiled by FYIcenter.com DBA team on Using Cursors in SQL Server Transact-SQL. Clear explanati...
2016-10-17, 356👍, 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, 356👍, 0💬

"mysql" - Command Line End User Interface in MySQL
What Is the Command Line End User Interface - mysql in MySQL? "mysql", official name is "MySQL monitor", is a command-line interface for end users to manage user data objects. "mysql" has the following main features: "mysql" is command line interface. It is not a Graphical User Interface (GUI). "mys...
2018-04-28, 355👍, 0💬

Decrementing a Date by 1 in MySQL
How To Decrement Dates by 1 in MySQL? If you have a date, and you want to decrement it by 1 day, you can use the DATE_SUB(date, INTERVAL 1 DAY) function. You can also use the date interval subtraction operation as "date - INTERVAL 1 DAY". The tutorial exercise below gives you some good examples: SEL...
2017-12-26, 355👍, 0💬

Using Subqueries in the FROM Clause in MySQL
How To Use Subqueries in the FROM clause in MySQL? 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 you mus...
2017-12-21, 355👍, 0💬

Renaming Database Names in SQL Server
How to rename databases in SQL Server? If don't like the name of a database, you can change it by using the "ALTER DATABASE" statement with the following syntax: ALTER DATABASE database_name MODIFY NAME = new_database_name The tutorial example below shows you how change the database name from "FyiCe...
2016-11-24, 355👍, 0💬

Determining Data Types of View Columns in SQL Server
How Column Data Types Are Determined in a View in SQL Server? When you define a view, its columns are defined through a list of expressions in the underlying SELECT statement. Their data types will be determined implicitly by the expressions. For example, if the column expression is a column name of...
2016-11-03, 355👍, 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, 355👍, 0💬

Converting Numeric Values to Character Strings in MySQL
How To Convert Numeric Values to Character Strings in MySQL? You can convert numeric values to character strings by using the CAST(value AS CHAR) function as shown in the following examples: SELECT CAST(4123.45700 AS CHAR) FROM DUAL; 4123.45700 -- How to get rid of the last 2 '0's? SELECT CAST(4.123...
2018-03-28, 354👍, 0💬

Run-Away Recursive Calls in Oracle
What Happens If Recursive Calls Get Out of Control in Oracle? What happens if your code has bug on recursive procedure calls, which causes an infinite number nested procedure calls? The answer is not so good. Oracle server seems to offer no protection calling stack limit. The script below shows you ...
2018-03-18, 354👍, 0💬

Ways to Start MySQL Server in MySQL
How To Start MySQL Server Daemon mysqld in MySQL? There are a number of ways to start MySQL server daemon, mysqld: Double click on the file name, mysqld.exe, in a file explorer window. This is an easy way to start the server. But you will not be able to specify any command line options. Enter "mysql...
2017-12-04, 354👍, 0💬

What Is a Database in SQL Server
What is a database in SQL Server? A database is a logical container that contains a set of related database objects: Tables - Storages of structured data. Views - Queries to present data from tables. Indexes - Sorting indexes to speed up searches. Stored Procedures - Predefined SQL program units. Us...
2016-11-24, 354👍, 0💬

Creating Databases with Specified Physical Files in SQL Server
How to create database with physical files specified in SQL Server? If you don't like the default behavior of the CREATE DATABASE statement, you can specify the physical database files with a longer statement: CREATE DATABASE database_name ON (NAME = logical_data_name, FILENAME = physical_data_name,...
2016-11-24, 354👍, 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, 354👍, 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, 354👍, 0💬

What Is a Procedure in Oracle
What Is a Procedure in Oracle? A procedure is a named program unit. It consists of three parts: Declaration Part - Defining the procedure name, calling parameters, local variables and local procedures. Declaration part is required. Execution Part - Defining execution logic with executable statements...
2018-01-27, 353👍, 0💬

Using Group Functions in the ORDER BY Clause in MySQL
Can Group Functions Be Used in the ORDER BY Clause in MySQL? 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 links were created in each year in each tag. The group output is sorted by the c...
2017-12-31, 353👍, 0💬

"INSERT" and "UPDATE" Statements - Inserting and Updating Data In Tables in SQL Server
How to insert and update data into a table with "INSERT" and "UPDATE" statements in SQL Server? This is the third tutorial of a quick lesson on creating database objects with Transact-SQL statements. This lesson shows you how to create a database, create a table in the database, and then access and ...
2016-12-02, 353👍, 0💬

Duplicate Key Error on Primary Key Columns in SQL Server
What Happens If You Insert a Duplicate Key for the Primary Key Column in SQL Server? If your table has a primary key column, and you are trying to insert a new row with duplicate key value on the primary key column, you will get an error. The reason is simple - Primary key column does not allow dupl...
2016-11-02, 353👍, 0💬

What Are Cursors in SQL Server
What Are Cursors in SQL Server Transact-SQL? A cursor is a special data type that represents a result set returned by a SELECT query statement. There are several notes about cursor you need to remember: Cursor data type can not be used to define table columns. Cursor data type is used on store proce...
2016-10-17, 353👍, 0💬

What Is a Cursor Variable in Oracle
What Is a Cursor Variable in Oracle? A cursor variable is a variable of a specific REF CURSOR data type, which is a pointer to a data structure resource connects to query statement result, similar to the CURSOR data type.. The advantage of using cursor variables is that cursor variables can be used ...
2018-04-07, 352👍, 0💬

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