Basic ms sql queries pdf

This is the default value, so you can also omit this keyword if you want the results in ascending order. We can see that the two Fluffys are a different order in each result we can tell by looking at their PetId values.

This is because the PetName column was sorted first, then the PetId sorted any duplicates from the first sorting. In this case, we can infer from these results that Tweet is the youngest pet, and Meow is the oldest. This is because we sorted by their date of birth DOB column in descending order. But this demonstrates that NULL values are treated as the lowest possible values.

Be mindful of NULL values when running queries. In this example, we search for all pets whose names start with the letter F. It is a function that takes the name of a column as argument and counts the number of rows when the column is not NULL.

It is used to create a new table in a database and specify the name of the table and columns inside it. It is a function that takes number of columns as an argument and return the largest value among them. It is a function that takes number of columns as an argument and return the smallest value among them. It is an operator that is used to filter the result set to contain only the rows where either condition is TRUE.

It is a clause used to sort the result set by a particular column either numerically or alphabetically. It is a function that takes the column name and a integer as an argument, and rounds the values in a column to the number of decimal places specified by an integer.

It is used to specify that the statement is a query which returns unique values in specified columns. It is a clause used to filter the result set to include the rows which where the condition is TRUE. It is used in practically all technologies that process data. If there's no matching row, NULL s are returned as values from the second table.

If there's no matching row, NULL s are returned as values from the left table. There are two syntaxes available. It computes summaries aggregates for each unique combination of values. A subquery is a query that is nested inside another query, or inside another subquery. There are different types of subqueries.

The simplest subquery returns exactly one column and exactly one row. A subquery can also return multiple columns or multiple rows. A correlated subquery refers to the tables introduced in the outer query. A correlated subquery depends on the outer query.