What is like %% in SQL?
The LIKE operator is used in a WHERE clause to search for a specified pattern in a column. There are two wildcards often used in conjunction with the LIKE operator: The percent sign (%) represents zero, one, or multiple characters. The underscore sign (_) represents one, single character.
What is ### in SQL?
The pound sign # is used to prefix temporary tables and procedures. A single instance ( # ) refers to a temporary object that lives/dies with the current session while a double instance ( ## ) is a global object.
What is SQL wildcard?
MySQL Wildcards A wildcard character is used to substitute one or more characters in a string. Wildcard characters are used with the LIKE operator. The LIKE operator is used in a WHERE clause to search for a specified pattern in a column.
IS NULL operator in SQL?
The IS NULL operator is used to test for empty values (NULL values).
What does \t mean in SQL?
T-SQL, which stands for Transact-SQL and is sometimes referred to as TSQL, is an extension of the SQL language used primarily within Microsoft SQL Server. This means that it provides all the functionality of SQL but with some added extras.
What does the symbol * represent in a SELECT query?
You can obviously retrieve multiple columns for each record, and (only if you want to retrieve all the columns) you can replace the list of them with * , which means “all columns”. So, in a SELECT statement, writing * is the same of listing all the columns the entity has.
What does symbol do in SQL?
Arithmetic Operators
| Symbol | Operation |
|---|---|
| + | Addition |
| – | Subtraction |
| * | Multiplication |
| / | Division |
What is the use of Alias?
Definition of alias : otherwise called : otherwise known as —used to indicate an additional name that a person (such as a criminal) sometimes uses John Smith alias Richard Jones was identified as the suspect.
Is NULL or empty in SQL?
NULL is used in SQL to indicate that a value doesn’t exist in the database. It’s not to be confused with an empty string or a zero value. While NULL indicates the absence of a value, the empty string and zero both represent actual values.
How do you DELETE NULL rows in SQL?
Use the delete command to delete blank rows in MySQL. delete from yourTableName where yourColumnName=’ ‘ OR yourColumnName IS NULL; The above syntax will delete blank rows as well as NULL row.
What does left join in SQL mean?
The LEFT JOIN command returns all rows from the left table, and the matching rows from the right table. The result is NULL from the right side, if there is no match.
Is T-SQL and SQL same?
Difference between T-SQL and SQL While T-SQL is an extension to SQL, SQL is a programming language. T-SQL contains procedural programming and local variable, while SQL does not. T-SQL is proprietary, while SQL is an open format.