When all arguments ( match_expression, pattern, and escape_character, if present) are ASCII character data types, ASCII pattern matching is performed. LIKE supports ASCII pattern matching and Unicode pattern matching. Uses AdventureWorksĬREATE PROCEDURE FindEmployee VARCHAR(20) However, the following example succeeds because trailing blanks aren't added to a varchar variable. This procedure fails because the trailing blanks are significant. Because the LastName column is varchar, there are no trailing blanks. In the FindEmployee procedure, no rows are returned because the char variable ( contains trailing blanks whenever the name contains fewer than 20 characters. WHERE p.LastName LIKE FindEmployee = 'Barb' Uses AdventureWorksįROM Person.Person p JOIN Person.Address a ON p.BusinessEntityID = a.AddressID The following example passes a local char variable to a stored procedure and then uses pattern matching to find all employees whose last names start with the specified set of characters. If a comparison in a query is to return all rows with the string LIKE 'abc' (abc without a space), all rows that start with abc and have zero or more trailing blanks are returned.Ī string comparison using a pattern that contains char and varchar data may not pass a LIKE comparison because of how the data is stored for each data type. However, trailing blanks, in the expression to which the pattern is matched, are ignored. If a comparison in a query is to return all rows with a string LIKE 'abc ' (abc followed by a single space), a row in which the value of that column is abc (abc without a space) isn't returned. Significant characters include any leading or trailing spaces. When you do string comparisons by using LIKE, all characters in the pattern string are significant. LIKE returns TRUE if the match_expression matches the specified pattern. escape_character is a character expression that has no default and must evaluate to only one character. Is a character put in front of a wildcard character to indicate that the wildcard is interpreted as a regular character and not as a wildcard. WHERE au_lname LIKE 'de%' finds all author last names starting with de and where the following letter isn't l. In range searches, the characters included in the range may vary depending on the sorting rules of the collation.Īny single character not within the specified range () or set (). WHERE au_lname LIKE 'arsen' finds author last names ending with arsen and starting with any single character between C and P, for example Carsen, Larsen, Karsen, and so on. WHERE au_fname LIKE '_ean' finds all four-letter first names that end with ean (Dean, Sean, and so on).Īny single character within the specified range () or set (). WHERE title LIKE '%computer%' finds all book titles with the word 'computer' anywhere in the book title. Is the specific string of characters to search for in match_expression, and can include the following valid wildcard characters. Is any valid expression of character data type. To view Transact-SQL syntax for SQL Server 2014 and earlier, see Previous versions documentation. Syntax for Azure Synapse Analytics and Parallel Data Warehouse Transact-SQL Syntax Conventions Syntax - Syntax for SQL Server and Azure SQL Database If any one of the arguments isn't of character string data type, the SQL Server Database Engine converts it to character string data type, if it's possible. Using wildcard characters makes the LIKE operator more flexible than using the = and != string comparison operators. However, wildcard characters can be matched with arbitrary fragments of the character string. During pattern matching, regular characters must exactly match the characters specified in the character string. A pattern can include regular characters and wildcard characters. Determines whether a specific character string matches a specified pattern.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |