The /* is the beginning of a comment and */ is the end of comment. Let us implement and display how to create a comment mysql> /* This is the first MySQL Program */ MySQL will ignore the above comment. Let us see an example.
What is /* in MySQL?
Standard SQL uses the C syntax /* this is a comment */ for comments, and MySQL Server supports this syntax as well. MySQL also support extensions to this syntax that enable MySQL-specific SQL to be embedded in the comment, as described in Section 9.7, “Comments”. The statement produces no change in value at all.
Which is the comment symbol in MySQL * 1 point && /* */?
In MySQL, the — (double-dash) comment style requires the second dash to be followed by at least one whitespace or control character (such as a space, tab, newline, and so on).
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.
Which is the comment symbol in MySQL * 1 point && /* */?
In MySQL, the — (double-dash) comment style requires the second dash to be followed by at least one whitespace or control character (such as a space, tab, newline, and so on).
What is the * symbol called in SQL?
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 are the symbols used to declare multiple line comments * /* /* */?
Multi-line comment Represented as /* any_text */ start with forward slash and asterisk (/*) and end with asterisk and forward slash (*/). It is used to denote multi-line comment.
What are wildcards in MySQL?
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 * a wildcard in SQL?
To broaden the selections of a structured query language (SQL-SELECT) statement, two wildcard characters, the percent sign (%) and the underscore (_), can be used. The percent sign is analogous to the asterisk (*) wildcard character used with MS-DOS.
What does the asterisk (*) symbol in a SELECT query retrieve?
The SELECT clause allows us to specify a comma-separated list of attribute names corresponding to the columns that are to be retrieved. You can use an asterisk character, *, to retrieve all the columns.
Should you use * in SQL?
That’s all about why you should not use SELECT * in the SQL query anymore. It’s always better to use the explicit column list in the SELECT query than a * wildcard. It not only improves the performance but also makes your code more explicit.
Is NULL or is not NULL?
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.
Is NULL in MySQL?
In MySQL, 0 or NULL means false and anything else means true. The default truth value from a boolean operation is 1 .
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.
Is * a wildcard in SQL?
To broaden the selections of a structured query language (SQL-SELECT) statement, two wildcard characters, the percent sign (%) and the underscore (_), can be used. The percent sign is analogous to the asterisk (*) wildcard character used with MS-DOS.
Which is the comment symbol in MySQL * 1 point && /* */?
In MySQL, the — (double-dash) comment style requires the second dash to be followed by at least one whitespace or control character (such as a space, tab, newline, and so on).
What does the * asterisk represent in a SQL statement?
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 is this symbol (*) used for?
An asterisk is a star-shaped symbol (*) that has a few uses in writing. It is most commonly used to signal a footnote, but it is sometimes also used to clarify a statement or to censor inappropriate language.
Why do they call this symbol (*) an asterisk?
The asterisk (/ˈæst(ə)rɪsk/ *), from Late Latin asteriscus, from Ancient Greek ἀστερίσκος, asteriskos, “little star”, is a typographical symbol. It is so called because it resembles a conventional image of a heraldic star.
What is a multi-line comment?
Multiline comments are used for large text descriptions of code or to comment out chunks of code while debugging applications. Comments are ignored by the compiler.
What is a comment symbol?
As you read the code examples, you often encounter the comment symbol ( ‘ ). This symbol tells the Visual Basic compiler to ignore the text following it, or the comment. Comments are brief explanatory notes added to code for the benefit of those reading it.
How do you comment over multiple lines?
Select all the lines that you would like to be commented. Two slashes “//” will be added to the front of each line, causing them to be recognized as a comment.
