utf8mb4_bin utf8mb4_0900_as_ci utf8mb4_0900_ai_ci utf8mb4_general_ci

utf8mb4_bin utf8mb4_0900_as_ci utf8mb4_0900_ai_ci utf8mb4_general_ci-- 1. utf8mb4_bin严格区分大小写重音 CREATE TABLE test_bin ( name VARCHAR(20) COLLATE utf8mb4_bin ); INSERT INTO test_bin VALUES (e), (E), (é), (É), (a), (A); -- 2. utf8mb4_0900_ai_ci大小写、重音都不区分 CREATE TABLE test_0900_ai_ci ( name VARCHAR(20) COLLATE utf8mb4_0900_ai_ci ); INSERT INTO test_0900_ai_ci VALUES (e), (E), (é), (É), (a), (A); -- 3. utf8mb4_0900_as_ci区分大小写、不区分重音 CREATE TABLE test_0900_as_ci ( name VARCHAR(20) COLLATE utf8mb4_0900_as_ci ); INSERT INTO test_0900_as_ci VALUES (e), (E), (é), (É), (a), (A); -- 4. utf8mb4_general_ci不区分大小写、重音不保证 CREATE TABLE test_general_ci ( name VARCHAR(20) COLLATE utf8mb4_general_ci ); INSERT INTO test_general_ci VALUES (e), (E), (é), (É), (a), (A); -- 统一验证查询看差异 SELECT utf8mb4_bin AS rule, * FROM test_bin WHERE name e; SELECT utf8mb4_0900_ai_ci AS rule, * FROM test_0900_ai_ci WHERE name e; SELECT utf8mb4_0900_as_ci AS rule, * FROM test_0900_as_ci WHERE name e; SELECT utf8mb4_general_ci AS rule, * FROM test_general_ci WHERE name e;