Jammy 
Pattern matching is used by the shell commands such as the ls command, whereas regular expressions are used to search for strings of text in a file by using commands, such as the grep command. Which command is used to match strings? Pattern matching is used by the shell commands such as the ls command, whereas regular expressions are used …
If you need to check a single database, you can quickly find the SQL Server database sizein SQL Server Management Studio (SSMS): Right-click the database and then click Reports -> Standard Reports -> Disk Usage. Alternatively, you can use stored procedures like exec sp_spaceused to get database size. How do I find the size of a database? You can find …
In MySQL, you can use the or != operators to test for inequality in a query. For example, we could test for inequality using the operator, as follows: SELECT * FROM contacts WHERE last_name ‘Johnson’; What does != Mean in a query? means not equal to, != also means not equal to. How do you use not equal to in …
The basic SQL structure is the same — all databases support SELECT , FROM , GROUP BY , and similar constructs. However, there are definitely differences among databases. Much of what you have learned will apply to other databases, but it is worth testing to be sure that it works and does what you intend. How many SQL syntax are …
The ISNULL() function returns 1 or 0 depending on whether an expression is NULL. If expression is NULL, this function returns 1. Otherwise, it returns 0. IS NULL function in MySQL? The ISNULL() function returns 1 or 0 depending on whether an expression is NULL. If expression is NULL, this function returns 1. Otherwise, it returns 0. Is NULL and …
The IS NULL condition is satisfied if the column contains a null value or if the expression cannot be evaluated because it contains one or more null values. If you use the IS NOT NULL operator, the condition is satisfied when the operand is column value that is not null, or an expression that does not evaluate to null. What …
That is why you should not use SELECT * in an SQL query anymore. It’s always better to use the explicit column list in a SELECT query than a * wild card. It not only improves performance but also makes your code more explicit. Why should we not use * in SQL? SELECT * return more data than required to …
The symbol Asterisk (*) in a select query retrieves all data from the table. What does asterisk (*) mean in SQL? The asterisk or star symbol ( * ) means all columns. The semi-colon ( ; ) terminates the statement like a period in sentence or question mark in a question. What does an asterisk (*) indicate? An asterisk is …
C:\Program Files\Microsoft SQL Server\MSSQL{nn}. How do I find the location of a database? If you ever need to know where your database files are located, run the following T-SQL code: USE master; SELECT name ‘Logical Name’, physical_name ‘File Location’ FROM sys. master_files; This will return a list of all data files and log files for the SQL Server instance. Where …
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. What does the * wildcard mean in SQL? A wildcard character is used to substitute one or more characters in …