You update records in a table using the UPDATE statement. When you use UPDATE, you must specify the name of the table whose records are being updated, as well as which fields you want to update. For example, the following query updates #TEMP, setting the credit limit field to 500 for all records:

UPDATE #TEMP SET "Credit Limit" = 500

The preceding statement updates all records in the table. In most cases, however, you will want to update only specific records. To specify which records to update, use a WHERE clause. For example, the following statement sets the Active field to False for those records where the Active field has not been assigned a value:

UPDATE #TEMP
 SET [Active] = False
 WHERE [Active] IS NULL

Here is another example:

UPDATE #TEMP
 SET [Credit Limit] = 0
 WHERE [Active] = False

The UPDATE statement also supports a FROM clause. You use FROM if you are using fields and expressions involving another table to perform the update. For example, the following UPDATE statement changes the Credit Limit field to 10000 for all records in #TEMP where the full name is associated with an employee record, and that employee's department code is 108:

UPDATE #TEMP
 SET "Credit Limit" = 10000
 FROM EMPLOYEE Emp INNER JOIN #TEMP ON
   "Full Name" =
     RTRIM(Emp."First Name") + ' ' + RTRIM(Emp."Last Name")
 WHERE Emp."Department Code" = 108