This particular collation happens to compare byte-by-byte (which is why it's called "binary" - it doesn't give any special meaning to strings). Return cmp ? cmp : (int)((t_is_prefix ? len : slen) - tlen) Here is an example of a binary collation from MySQL: static int my_strnncoll_binary(const CHARSET_INFO *cs _attribute_((unused)), A collation is a library that has various rules for comparing strings. What does this mean? It means that when comparing strings, the = operator is just a thin wrapper around the current collation. Strings, the specific value selected by these operations fromĪ set of such equal values is implementation-dependent. UNION, EXCEPT, and INTERSECT operators refer to character MAX, MIN, DISTINCT, references to a grouping column, and the Otherwise, the pad character is aī) The result of the comparison of X and Y is given by theĬ) Depending on the collating sequence, two strings mayĬompare as equal even if they are of different lengths orĬontain different sequences of characters. Implementation-dependent character different from anyĬharacter in the character set of X and Y that collates less IfĬS has the NO PAD attribute, then the pad character is an String by concatenation on the right of one or more padĬharacters, where the pad character is chosen based on CS. Itself that has been extended to the length of the longer Replaced, for the purposes of comparison, with a copy of In characters of Y, then the shorter string is effectively The comparison of two character strings is determined as follows:Ī) If the length in characters of X is not equal to the length The SQL Standard § 8.2 describes how = compares strings:
SQL LIKE VS ILIKE MANUAL
Please note that this page of the MySQL manual is called String Comparison Functions, and = is not discussed, which implies that = is not strictly a string comparison function. Mysql> SELECT 'ä' = 'ae' COLLATE latin1_german2_ci | 'ä' LIKE 'ae' COLLATE latin1_german2_ci | Per the SQL standard, LIKE performs matching on a per-character basis, thus it can produce results different from the = comparison operator: mysql> SELECT 'ä' LIKE 'ae' COLLATE latin1_german2_ci Let us first identify an example where these operators produce obviously different results. To complicate matters, both operators use a collation which can have important effects on the result of the comparison. LIKE is a string operator that compares character by character. When comparing strings, the comparison operator compares whole strings. = is a comparison operator that operates on numbers and strings. Most answers here focus on the wildcard support, which is not the only difference between these operators!
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