{"id":426,"date":"2024-08-28T08:47:14","date_gmt":"2024-08-28T08:47:14","guid":{"rendered":"https:\/\/techkubo.com\/sql\/?p=426"},"modified":"2025-05-25T03:31:18","modified_gmt":"2025-05-25T03:31:18","slug":"case","status":"publish","type":"post","link":"https:\/\/techkubo.com\/sql\/case\/","title":{"rendered":"CASE"},"content":{"rendered":"\n

SQL CASE Keyword<\/h2>\n\n\n\n

The CASE keyword in SQL is used to create conditional logic in a query. It allows you to return different values based on specific conditions \u2014 similar to an IF-THEN-ELSE statement.<\/p>\n\n\n\n

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SQL CASE Syntax<\/h2>\n\n\n\n
SELECT column1,\nCASE\n    WHEN condition1 THEN result1\n    WHEN condition2 THEN result2\n    ...\n    ELSE result_default\nEND AS alias_name\nFROM table_name;<\/pre><\/div>\n\n\n\n
You can also use CASE inside an ORDER BY clause:<\/p>\n\n\n\n
SELECT column1, column2\nFROM table_name\nORDER BY\nCASE\n    WHEN condition THEN sort_column1\n    ELSE sort_column2\nEND;<\/pre><\/div>\n\n\n\n
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SQL CASE Example with Appointments Table<\/h2>\n\n\n\n
The following SQL statement shows the appointment ID, status, and a label that changes depending on the value of the status column. This query returns all appointment records and adds a new column status_label based on the value of status.<\/p>\n\n\n\n
SELECT appointment_id, status,\nCASE\n    WHEN status = 'Confirmed' THEN 'Confirmed'\n    WHEN status = 'Scheduled' THEN 'Waiting'\n    ELSE 'Unknown Status'\nEND AS status_label\nFROM Appointments;<\/pre><\/div>\n\n\n\n
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Try It Out!<\/a><\/div>\n<\/div>\n\n\n\n
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SQL CASE Example in ORDER BY Clause (Patients Table)<\/h2>\n\n\n\n
This example orders the patients by last_name, but if last_name is NULL, it will order by first_name instead. This ensures that even rows with missing last names are properly sorted using first names. <\/p>\n\n\n\n
SELECT first_name, last_name\nFROM Patients\nORDER BY\nCASE\n    WHEN last_name IS NULL THEN first_name\n    ELSE last_name\nEND;<\/pre><\/div>\n\n\n\n
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SQL CASE Labs<\/h2>\n\n\n\n