Unlike the LIKE function, string matching is case-insensitive. 1.3 What is the ILIKE operator The ILIKE operator in sql query is similar to LIKE but it matches values case-insensitively. It is represented by the below syntax LIKE condition in sql. Then you can get the values that match the pattern mentioned by using the LIKE query in SQL. Or: how to compare chars from different languages? How to compare Cyrillic "T" to latin "T"? In UTF/Unicode such comparison is possible (and Vertica data encoded in UTF-8). Allows matching of strings based on comparison with a pattern. 1.2 What is a LIKE operator The LIKE operator in SQL query is used with the where keyword and helps to fetch records based on the pattern matching. When you only know a fragment of a text value and need to get the details from the table. FYI: For UTF/Unicode its a big problem/challenge - case sensitive comparison, because same letters in different languages can has different order. the 'like' expression is different in that is uses pattern matching to find the correct values, and as such requires a bit more work in the back end. The LIKE command is used in a WHERE clause to search for a specified pattern in a column. The SQL LIKE Operator The LIKE operator is used in a WHERE clause to search for a specified pattern in a column. I don't know what strategy Vertica choose, both strategies has same complexity in worst case => O(length of string). Can be another strategy: convert all strings to same case (lower or upper) and prepare case-sensitive comparison. test=> select ascii('a'), ascii('A'), 'a' > 'A' ascii | ascii | ?column? -+-+- 97 | 65 | t (1 row) So non-case sensitive search require 2 comparison for decision: character compared to "small" AND "capital" letter. For example ASCII table comparison: small "a" = 97, while capital "A" = 65. Hi! Case-sensitive search ALWAYS will be faster than non sensitive, because it compares chars by their order in characters table.
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