How to Efficiently Concatenate Columns and Text in Oracle SQL?

Mastering String Concatenation in Oracle SQL

Efficiently combining multiple columns and static text is a frequent task in Oracle SQL. This guide demonstrates how to create a single, unified string column by merging data from various fields.

Methods for Concatenation:

Oracle provides two primary methods for string concatenation:

• CONCAT Function: This function sequentially joins multiple strings, ideal for building complex, dynamic concatenations.
• || Operator: The double pipe operator offers a more concise approach, directly appending strings without the need for a separate function.

Illustrative Example:

Let's use a Cake_Info table to demonstrate:

CREATE TABLE Cake_Info (
  cake_id NUMBER,
  type_desc_column VARCHAR2(20),
  icing_desc_column VARCHAR2(20),
  fruit_desc_column VARCHAR2(20)
);

Sample data:

INSERT INTO Cake_Info (cake_id, type_desc_column, icing_desc_column, fruit_desc_column) VALUES (1, 'chocolate', 'whipped_cream', 'cherry');
INSERT INTO Cake_Info (cake_id, type_desc_column, icing_desc_column, fruit_desc_column) VALUES (2, 'strawberry', 'vanilla_cream', 'lemon_slice');

Using the CONCAT Function:

SELECT CONCAT(
  CONCAT(
    CONCAT(
      CONCAT('I like ', type_desc_column), ' cake with '), icing_desc_column),
    ' and a '), fruit_desc_column)
FROM Cake_Info;

Using the || Operator:

SELECT 'I like ' || type_desc_column || ' cake with ' || icing_desc_column || ' and a ' || fruit_desc_column
FROM Cake_Info;

Both queries produce this output:

<code>Cake_Column
----------------
I like chocolate cake with whipped_cream and a cherry.
I like strawberry cake with vanilla_cream and a lemon_slice.</code>

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