The difference between like and = in sql

LIKE and = are operators used for string comparison in SQL. The main difference is that LIKE allows wildcard fuzzy matching (% and _), while = only works for exact matches. LIKE is suitable for fuzzy queries, has slower performance, and cannot use indexes. = is used for exact matching, faster performance, and indexing can be used. The choice of operator depends on the specific matching requirements of the query.

The difference between LIKE and = in SQL

Clear the difference:

LIKE and = are the two major operators used to compare strings in SQL. The main difference is that LIKE allows wildcard characters (% and _), while = can only match the exact same string.

Detailed answer:

LIKE

• ##Wildcard:

  %: Matches any number of characters (including 0)
  • _: Matches a single character
• Syntax: FIELD LIKE 'PATTERN'
• Usage: Widely used for fuzzy queries, such as finding strings that start or end with specific characters.

=

• Exact match:

  Only matches the specified Strings with exactly the same value
• Syntax: FIELD = 'VALUE'
• Usage: Used for exact matching, such as finding specific records with specific values.

Example:

• LIKE:

  • SELECT * FROM customers WHERE name LIKE '%Smith'
  Find all customers whose last name ends with "Smith".

• =：

  • SELECT * FROM orders WHERE order_id = 12345
  Find the order with order ID 12345.

Other differences:

• Performance: LIKE queries are generally slower than = queries because They involve fuzzy matching, requiring more complex comparisons to be performed.
• Index: LIKE queries generally cannot use index optimization, while = queries can.
• NULL values: LIKE returns NULL when comparing NULL values, while = returns FALSE.

Choose:

Select LIKE or = depending on the specific requirements of the query:

• Use LIKE:

  When fuzzy matching is required.

• Use =:

  When an exact match is required and performance and indexability are a priority factor.

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