SQL DEFAULT Constraint

The SQL DEFAULT Constraint is used to set a default value to a column when we insert a new row to a table without providing a value for the column.

We can use the DEFAULT keyword to specify a default value for a column.

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SQL NOT NULL Constraint

By default, a column can hold NULL value. The SQL NOT NULL Constraint is used to force a column cannot accept a NULL value, and must hold a value.

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SQL Create Table

SQL table is a place where the SQL database stores the data. It has columns and rows. We can use CREATE TABLE statement to create a table in a database.

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ORACLE TO_CHAR

Oracle To_char() is an SQL function which will convert a number or date to string.

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SQL REVERSE

SQL REVERSE function is used to return reverse of a string. It’s supported by MS SQL Server, MySQL. Oracle supports it too, but maybe not in the documents.

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The Difference Among char, nchar, varchar, nvarchar in MS SQL Server

In MS SQL Server, there are some data types of string, like char, nchar, varchar, nvarchar. What’s the difference among them?
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SQL LEFT Function

SQL LEFT() function is used to get left part of a string with the length of specified number. It is supported by MySQL, MS SQL Server, Access, but not by Oracle.

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SQL SPACE

SQL SPACE() function is used to return space characters, the number of the characters is indicated by the interger parameter. It is supported by MySQL and MS SQL Server, but not Oracle.

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SQL CHAR

SQL CHAR function is used to return a character of an int ASCII code.

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SQL Hosting

SQL hosting is the hosting that provides the SQL database services. It has many SQL databases in the SQL hosting market, and the most popular are MySQL, MS SQL Server, MS Access and Oracle.
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