How do you join two tables based on conditions?
You join two tables by creating a relationship in the WHERE clause between at least one column from one table and at least one column from another. The join creates a temporary composite table where each pair of rows (one from each table) that satisfies the join condition is linked to form a single row.
Can you join on two conditions SQL?
The SQL AND condition and OR condition can be combined to test for multiple conditions in a SELECT, INSERT, UPDATE, or DELETE statement. When combining these conditions, it is important to use parentheses so that the database knows what order to evaluate each condition.
What does (+) mean in SQL joins?
Oracle outer join operator (+) allows you to perform outer joins on two or more tables.
How do I do a conditional sum in SQL?
A method to simplify this query and to run within a single select that I have used with success is to use a “conditional” sum in the SQL query. So rather than running COUNT(*) we will be running SUM(…) . We will combine the SUM() call with a CASE statement, so that it counts correctly.
Conditional Sums in SQL Aggregate Methods.
Can we use WHERE with join in SQL?
Yes. ON should be used to define the join condition and WHERE should be used to filter the data. … To go more in depth we will cover the two use cases that either WHERE or ON can support: Joining data.
What is equi join?
An equi-join is a basic join with a WHERE clause that contains a condition specifying that the value in one column in the first table must be equal to the value of a corresponding column in the second table.
How do I have multiple rows in one row in SQL?
STUFF Function in SQL Server
- Create a database.
- Create 2 tables as in the following.
- Execute this SQL Query to get the student courseIds separated by a comma. USE StudentCourseDB. SELECT StudentID, CourseIDs=STUFF. ( ( SELECT DISTINCT ‘, ‘ + CAST(CourseID AS VARCHAR(MAX)) FROM StudentCourses t2.
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 … …
How do I Lookup multiple values in SQL?
Yes, you can use SQL IN operator to search multiple absolute values: SELECT name FROM products WHERE name IN ( ‘Value1’, ‘Value2’, … );
How do I use NVL in SQL?
A final example using the NVL function in Oracle/PLSQL is: SELECT NVL(commission, 0) FROM sales; This SQL statement would return 0 if the commission field contained a null value. Otherwise, it would return the commission field.
What is use of with in SQL?
The SQL WITH clause allows you to give a sub-query block a name (a process also called sub-query refactoring), which can be referenced in several places within the main SQL query. … The SQL WITH clause was introduced by Oracle in the Oracle 9i release 2 database.
Can you do Sumif in SQL?
Excels SUMIF in SQL
The column is explicitly used in the <condition> that is put into the case expression. The case expression accepts different values in the when and then branches. This allows you to do the same thing as the third argument of the sumif function.
Can we use case inside sum in SQL?
The examples are included to bolster your understanding. Knowing how to use a CASE WHEN expression in SQL adds insight into the exciting possibilities in SQL. … Combined with other functions and statements, such as SUM() and GROUP BY, the CASE WHEN expression is a powerful tool for creating complex SQL reports.
What is conditional aggregation?
Conditional aggregation, as its name implies, is performing data aggregation over a set of data that meets certain condition which is contained within a given data range. In this “recipe” we’ll cover functions that use single condition for performing aggregation.