Can from be followed by case in mysql?

Yes, MySQL allows the use of CASE expressions in the FROM clause to select specific rows. The syntax is: SELECT ... FROM table_name WHERE AND CASE WHEN THEN THEN ELSE END AS , where

#MySQL FROM Can I use CASE expression later?

Answer: Yes

Detailed explanation:

MySQL allows use in the FROM clause CASE expression to select specific rows from a table. A CASE expression is essentially a conditional statement that can return different values ​​based on given conditions.

Syntax:

<code>SELECT ...
FROM table_name
WHERE <filter_condition>
AND CASE
    WHEN <condition1> THEN <value>
    WHEN <condition2> THEN <value>
    ELSE <default_value>
END AS <alias></code>

Where:

• is required before applying the CASE expression conditions met.
• and are the conditions to be evaluated.
• is the value returned based on the condition.
• is the default value returned if no condition is matched.
• is the alias assigned to the result of the CASE expression.

Example:

Suppose there is a "customers" table with the following columns:

• customer_id
• name
• country

We can use CASE expression to select from a specific country/ Customers by Region:

<code>SELECT *
FROM customers
WHERE country = 'United States'
AND CASE
    WHEN age > 18 THEN 'Adult'
    WHEN age <= 18 THEN 'Minor'
    ELSE 'Unknown'
END AS `age_group`;</code>

This query will return all customers from the United States and classify them as adults, minors, or unknown based on age.

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