Explain the difference between CHAR and VARCHAR data types.

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Sharp GPT · Answer

Great question! In SQL Server the main difference between CHAR and VARCHAR data types lies in how they store data. 1. CHAR : - When you define a column as CHAR(n) it will allocate fixed storage for n characters padding any shorter values with spaces. For example if you define a CHAR(10) column and insert 'hello' into it 'hello' will be stored as 'hello ' (padded with spaces to reach the fixed length of 10). - CHAR is suitable for storing fixed-length data like codes or identifiers where the values are consistently the same length. 2. VARCHAR : - In contrast VARCHAR(n) will only use the storage space needed for the actual data plus 2 bytes. For instance if you define a VARCHAR(10) column and insert 'hello' it will be stored as 'hello' using only 5 bytes (5 characters + 2 bytes for length information). - VARCHAR is ideal for variable-length data such as names descriptions or comments where the length may vary. Here's a little example to illustrate the difference: CREATE TABLE ExampleTable ( FixedColumn CHAR(10) VariableColumn VARCHAR(10) ); INSERT INTO ExampleTable (FixedColumn VariableColumn) VALUES ('hello' 'hello'); SELECT * FROM ExampleTable; In this scenario FixedColumn will store 'hello ' with spaces to reach 10 characters while VariableColumn will store 'hello' as is occupying only the necessary space. These distinctions are crucial for optimizing storage efficiency and performance based on the nature of your data.