4. Table Column Check in MySQL Similar to MSSQL,in MySQL, column existence checks are often performed using the INFORMATION SCHEMA database. As a matter of fact, this database stores metadata about all tables and columns within all the databases. In this case,we use theCOLUMNStable that con...
First, notice that we used COUNT(*) to count the rows for each group, which corresponds to the country. In addition, we also used the SQL alias to rename the column into a more explainable name. This is possible by using the keyword AS, followed by the new name. COUNT is covered in...
"Missing column specification" is a type of SQL compilation error, meaning that this error arises due to some incorrect syntax in the SQL query you're trying to process. 🛑 Specifically, the missing column specification error arises when you use Snowflake's data definition language (DDL) to ...
How do I check if EmpID EE# exists in SupervisorID column and categorize it based on Manager or Individual Contributor in OBIEE. Here's the table for reference. Currently, consider there are only 2 columns EmpID EE# and SupervisorID. I need a formula t...
In this tutorial, we’ll discuss various methods to efficiently count distinct values, with the appropriate examples. 2. Simple SQL Query for Unique Values Counting unique values in a SQL column is straightforward with theDISTINCTkeyword. Here, let’s see how to effectively count distinct entries...
The COALESCE() function takes in at least one value (value_1). It will return the first non-null value in the list, from left to right. For example, it will first check if value_1 is null. If not, then it returns value_1. Otherwise, it checks if value_2 is null. The process...
SQL check constraint and user-defined functions A scalar-valued user-defined function returns a single value after its invocation. We can use this type of function in the check constraints to define a data validation rule. At the same time, we can pass the inserted data value to this functio...
If you’ve been developing in SQL Server for any length of time, you’ve no doubt hit this scenario: You have an existing, working query that produces results your customers or business owners say are correct. Now, you’re asked to change something, or perhaps you find out your existing...
Which is used to count distinct visits in about 20 hospitals. This SQL will take more than 10 seconds to finish on their server. I did a test on my virtual machines with the same table but with populated data(6,000,000 records) then it will took about 16 seconds to finish the search...
I have Column A with many servernames which are often duplicated.Column B has a variety of dates.I want to count the number of unique servers for a specified...