How Write If Else In SQL Query?

How use multiple IF condition in SQL query?

If you are checking conditions against multiple variables then you would have to go for multiple IF Statements, Each block of code will be executed independently from other blocks.

ELSE IF(@ID IS NOT NULL AND @ID in (SELECT ID FROM Places)) — Outer Most Block ELSE IF BEGIN SELECT @MyName = Name …


Can we use if condition in where clause in SQL?

This is a very common technique in a WHERE clause. If you want to apply some “IF” logic in the WHERE clause all you need to do is add the extra condition with an boolean AND to the section where it needs to be applied. You don’t need a IF statement at all.

Can we write select statement in case?

The CASE expression is a conditional expression: it evaluates data and returns a result. … This expression can be used in SELECT , UPDATE , and DELETE statements or in WHERE , IN , LIKE , ORDER BY , and HAVING clauses. We’ll focus on the SELECT statement and use IN and LIKE operators.

Why do we use escape characters in SQL queries?

Escape Characters Use braces to escape a string of characters or symbols. Everything within a set of braces in considered part of the escape sequence. When you use braces to escape a single character, the escaped character becomes a separate token in the query.

How do you escape and in SQL query?

The first allows you to use the backslash to escape the &. The second turns off & “globally” (no need to add a backslash anywhere). You can turn it on again by set define on and from that line on the ampersands will get their special meaning back, so you can turn it off for some parts of the script and not for others.

How do you escape keywords in SQL?

To escape reserved keywords in SQL SELECT statements and in queries on views, enclose them in double quotes (”).

How do you write an if statement in SQL?

We can understand SQL IF Statement using the following flow chart.The condition in SQL IF Statement should return a Boolean value to evaluate.We can specify a Select statement as well in a Boolean expression, but it should enclose in parentheses.We can use BEGIN and END in the IF Statement to identify a statement block.More items…•

How do I query NULL values in SQL?

How to Test for NULL Values?SELECT column_names. FROM table_name. WHERE column_name IS NULL;SELECT column_names. FROM table_name. WHERE column_name IS NOT NULL;Example. SELECT CustomerName, ContactName, Address. FROM Customers. WHERE Address IS NULL; … Example. SELECT CustomerName, ContactName, Address. FROM Customers.

What is use of escape in SQL?

Escape sequences are used within an SQL statement to tell the driver that the escaped part of the SQL string should be handled differently. When the JDBC driver processes the escaped part of an SQL string, it translates that part of the string into SQL code that SQL Server understands.