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Can anyone point out how to check if a select query returns non empty result set? For example I have next query: SELECT * FROM service s WHERE s.service_id = ?; Should I do something like next: ISNULL(SELECT * FROM service s WHERE s.service_id = ?) to test if result set is not empty?
How do I check if a column is empty or null using a SQL select statement? For instance, if I want to check: select * from UserProfile WHERE PropertydefinitionID in (40, 53) and PropertyValue is null or empty
6 cze 2024 · In this article, we explored several techniques for identifying NULLs and empty values within a column. In SQL, NULL represents missing or unknown data, covering cases where data is absent or uncertain. We can use empty strings for similar purposes, allowing us to differentiate between the absence and nonexistence of data.
The IS NULL operator is used to test for empty values (NULL values). The following SQL lists all customers with a NULL value in the "Address" field:
4 sty 2011 · You set a varchar2 to an empty string like this: Update mytable set varchar_col = ''; the following leads to the same result. Update mytable set varchar_col = NULL; But to select the columns where the value is empty or NULL, you have to use. select * from mytable where varchar_col is NULL; Using . select * from mytable where varchar_col = '';
13 mar 2023 · In this SQL tutorial, we will discuss how to use the WHERE IS NOT NULL operator in SQL Server and explore some examples of using it in real-world scenarios. We will show, by examples, how to use the SQL WHERE IS NOT NULL statement to alter data in a test table in the following ways:
19 maj 2021 · Due to this structure of the NULL values, it is not possible to use traditional comparison (=, <, > and <>) operators in the queries. As a matter of fact, in the SQL Standards using the WHERE clause as the below will lead to return empty result sets.
