The following example finds all products that have NULL in the Weight column. Using IS NULL to test for NULL in a WHERE clause ISNULL(MinPaymentAmount,0) AS MinimumPayment The following example uses ISNULL to test for NULL values in the column MinPaymentAmount and display the value 0.00 for those rows. It substitutes the value 50 for all NULL entries in the Weight column of the Product table. The following example finds the average of the weight of all products in a sample table. USE AdventureWorks2012 Įxamples: Azure Synapse Analytics and Analytics Platform System (PDW) D. The following example finds all products that have NULL in the weight column.
Testing for NULL in a WHERE clauseĭo not use ISNULL to find NULL values. SELECT Description, DiscountPct, MinQty, ISNULL(MaxQty, 0.00) AS 'Max Quantity'
If the maximum quantity for a particular special offer is NULL, the MaxQty shown in the result set is 0.00. The following example selects the description, discount percentage, minimum quantity, and maximum quantity for all special offers in AdventureWorks2012. The following example finds the average of the weight of all products. You can use the NOT operator to negate the condition provided by the >= operator.Use COALESCE (Transact-SQL) to return the first non-null value. This resulted in only one city from Overijssel being returned, as opposed to two in the previous query. This time we got only those cities that satisfied both Population >= 100000 OR District = 'Overijssel' and Name >= 'Overijssel'. That would give us the same result as the previous query without parentheses.īut look what happens when we move the parentheses to the OR condition. This is like doing the following: SELECT * FROM city
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We can tell just by looking at this that all cities from the Overijssel district will be returned, plus any cities that satisfy the first criteria. Therefore we got rows that satisfied either Name >= 'Zukovski' AND Population >= 100000 or District = 'Overijssel'. In this query, I didn’t provide any parentheses, and so the AND operator was evaluated before the OR operator. | 15 | Enschede | NLD | Overijssel | 149544 | Parentheses have a higher precedence than all operators, and so you can use parentheses to specify the order in which each condition should be evaluated.Ĭonsider the following example: SELECT * FROM city It also evaluates any AND operators before any OR operators. For example, it evaluates any conditional operators before any logical operators, such as AND and OR. Note that SQL has an order of precedence that it assigns to different operator types. You can also use a combination of operators when filtering the results. WHERE Name >= 'Zukovski' AND Population >= 200000 If you have multiple conditions, you can use multiple >= operators. When comparing with a string value, use quotes around the string. You can also use the greater than or equal to operator to compare string values. Here’s an example to demonstrate using the greater than or equal to operator to compare date values. Or we could simply use the greater than ( >) operator instead: SELECT * FROM city If we wanted to exclude cities with that population, we would either need to increase the specified value: SELECT * FROM city The greater than or equal to operator includes the specified value in its evaluation.įor example, the previous query included Karachi, which, according to this database, has a population of exactly 9269265.
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In this free webinar, product experts Julie Hyman and John Pocknell wil. If you’re using Quest Toad for SQL Server, you’ll love ApexSQL by Quest. Free database webinar: Toad loves ApexSQL. This query returns all cities that have a population of greater than or equal to 9269265. Subscribe to Toad for SQL Server posts via RSS. | ID | Name | Countr圜ode | District | Population | In SQL, the greater than or equal to operator ( >=) compares two expressions and returns TRUE if the left operand has a value greater than or equal to the right operand otherwise, it returns FALSE.
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