What is the COALESCE function used for?

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What is the COALESCE function used for?

Daniel Steinhold Answered question July 31, 2023
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In Snowflake, the COALESCE function is used to return the first non-null expression from a list of expressions. It is commonly used to handle null values and provide a fallback value when encountering nulls. Here's the syntax for the COALESCE function in Snowflake:

```
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COALESCE(expr1, expr2, ...)

```

The COALESCE function takes two or more expressions as arguments and returns the first non-null expression. It evaluates the expressions in order from left to right and returns the value of the first non-null expression. If all expressions are null, the COALESCE function returns null.

Example usage:

```
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SELECT COALESCE(column1, column2, 'N/A') AS result FROM table;

```

In this query, if **`column1`** is not null, its value will be returned. If **`column1`** is null but **`column2`** is not null, the value of **`column2`** will be returned. If both **`column1`** and **`column2`** are null, the COALESCE function will return the fallback value **`'N/A'`**.

The COALESCE function is helpful when you need to provide a default or substitute value for null expressions. It allows you to handle null values in a concise and controlled manner, ensuring that a valid result is always returned.

By using the COALESCE function, you can simplify your queries and expressions by handling nulls effectively and providing alternative values or defaults when necessary.

Daniel Steinhold Answered question July 31, 2023

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