215 lines
6.8 KiB
SQL
215 lines
6.8 KiB
SQL
-- ================================================
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-- 删除冗余索引，恢复系统速度
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-- ================================================
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-- 问题：idx_student_id 与 uk_student_class 的第一列重复
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-- 导致：写入性能下降，系统变慢
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-- ================================================
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USE study;
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SELECT '开始删除冗余索引...' AS info;
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-- ================================================
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-- 1. 删除 student_class 表的冗余索引
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-- ================================================
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SELECT '删除 student_class.idx_student_id (冗余，uk_student_class已覆盖)' AS info;
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-- 检查索引是否存在
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SELECT COUNT(*) INTO @index_exists
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FROM information_schema.STATISTICS
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WHERE TABLE_SCHEMA = 'study'
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AND TABLE_NAME = 'student_class'
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AND INDEX_NAME = 'idx_student_id';
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-- 如果存在则删除
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SET @sql = IF(@index_exists > 0,
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'ALTER TABLE student_class DROP INDEX idx_student_id',
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'SELECT "idx_student_id 不存在" AS result'
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);
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PREPARE stmt FROM @sql;
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EXECUTE stmt;
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DEALLOCATE PREPARE stmt;
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-- ================================================
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-- 2. 删除 idx_class_id（如果不需要）
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-- ================================================
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-- 注意：只有当确认不需要单独的 class_id 查询时才删除
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-- 如果有 WHERE class_id = ? 的查询，建议保留
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SELECT '检查 idx_class_id 是否需要保留...' AS info;
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-- 暂时保留 idx_class_id，因为可能有按 class_id 查询的需求
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-- 如果确认不需要，取消下面的注释
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-- ALTER TABLE student_class DROP INDEX idx_class_id;
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SELECT 'idx_class_id 已保留（如果不需要可手动删除）' AS result;
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-- ================================================
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-- 3. 检查 sys_user 表的索引（可能也有冗余）
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-- ================================================
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SELECT '检查 sys_user 表索引...' AS info;
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SELECT
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INDEX_NAME AS '索引名',
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GROUP_CONCAT(COLUMN_NAME ORDER BY SEQ_IN_INDEX) AS '列',
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INDEX_TYPE AS '类型',
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CASE NON_UNIQUE WHEN 0 THEN '唯一' ELSE '非唯一' END AS '属性'
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FROM information_schema.STATISTICS
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WHERE TABLE_SCHEMA = 'study'
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AND TABLE_NAME = 'sys_user'
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GROUP BY INDEX_NAME, INDEX_TYPE, NON_UNIQUE
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ORDER BY INDEX_NAME;
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-- ================================================
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-- 建议删除的 sys_user 索引（如果是优化时添加的）
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-- ================================================
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SELECT '删除 sys_user 的优化索引（如果存在）...' AS info;
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-- idx_user_name（如果有唯一索引或其他索引覆盖）
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SET @sql = IF(
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EXISTS(SELECT 1 FROM information_schema.STATISTICS
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WHERE TABLE_SCHEMA = 'study' AND TABLE_NAME = 'sys_user'
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AND INDEX_NAME = 'idx_user_name'),
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'ALTER TABLE sys_user DROP INDEX idx_user_name',
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'SELECT "idx_user_name 不存在" AS result'
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);
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PREPARE stmt FROM @sql;
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EXECUTE stmt;
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DEALLOCATE PREPARE stmt;
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-- idx_nick_name
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SET @sql = IF(
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EXISTS(SELECT 1 FROM information_schema.STATISTICS
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WHERE TABLE_SCHEMA = 'study' AND TABLE_NAME = 'sys_user'
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AND INDEX_NAME = 'idx_nick_name'),
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'ALTER TABLE sys_user DROP INDEX idx_nick_name',
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'SELECT "idx_nick_name 不存在" AS result'
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);
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PREPARE stmt FROM @sql;
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EXECUTE stmt;
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DEALLOCATE PREPARE stmt;
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-- idx_email
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SET @sql = IF(
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EXISTS(SELECT 1 FROM information_schema.STATISTICS
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WHERE TABLE_SCHEMA = 'study' AND TABLE_NAME = 'sys_user'
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AND INDEX_NAME = 'idx_email'),
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'ALTER TABLE sys_user DROP INDEX idx_email',
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'SELECT "idx_email 不存在" AS result'
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);
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PREPARE stmt FROM @sql;
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EXECUTE stmt;
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DEALLOCATE PREPARE stmt;
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-- idx_dept_id
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SET @sql = IF(
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EXISTS(SELECT 1 FROM information_schema.STATISTICS
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WHERE TABLE_SCHEMA = 'study' AND TABLE_NAME = 'sys_user'
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AND INDEX_NAME = 'idx_dept_id'),
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'ALTER TABLE sys_user DROP INDEX idx_dept_id',
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'SELECT "idx_dept_id 不存在" AS result'
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);
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PREPARE stmt FROM @sql;
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EXECUTE stmt;
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DEALLOCATE PREPARE stmt;
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-- idx_status
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SET @sql = IF(
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EXISTS(SELECT 1 FROM information_schema.STATISTICS
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WHERE TABLE_SCHEMA = 'study' AND TABLE_NAME = 'sys_user'
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AND INDEX_NAME = 'idx_status'),
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'ALTER TABLE sys_user DROP INDEX idx_status',
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'SELECT "idx_status 不存在" AS result'
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);
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PREPARE stmt FROM @sql;
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EXECUTE stmt;
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DEALLOCATE PREPARE stmt;
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-- idx_del_flag
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SET @sql = IF(
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EXISTS(SELECT 1 FROM information_schema.STATISTICS
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WHERE TABLE_SCHEMA = 'study' AND TABLE_NAME = 'sys_user'
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AND INDEX_NAME = 'idx_del_flag'),
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'ALTER TABLE sys_user DROP INDEX idx_del_flag',
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'SELECT "idx_del_flag 不存在" AS result'
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);
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PREPARE stmt FROM @sql;
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EXECUTE stmt;
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DEALLOCATE PREPARE stmt;
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-- idx_register_type
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SET @sql = IF(
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EXISTS(SELECT 1 FROM information_schema.STATISTICS
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WHERE TABLE_SCHEMA = 'study' AND TABLE_NAME = 'sys_user'
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AND INDEX_NAME = 'idx_register_type'),
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'ALTER TABLE sys_user DROP INDEX idx_register_type',
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'SELECT "idx_register_type 不存在" AS result'
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);
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PREPARE stmt FROM @sql;
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EXECUTE stmt;
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DEALLOCATE PREPARE stmt;
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-- idx_student_status
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SET @sql = IF(
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EXISTS(SELECT 1 FROM information_schema.STATISTICS
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WHERE TABLE_SCHEMA = 'study' AND TABLE_NAME = 'sys_user'
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AND INDEX_NAME = 'idx_student_status'),
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'ALTER TABLE sys_user DROP INDEX idx_student_status',
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'SELECT "idx_student_status 不存在" AS result'
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);
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PREPARE stmt FROM @sql;
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EXECUTE stmt;
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DEALLOCATE PREPARE stmt;
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-- ================================================
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-- 4. 重新分析表
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-- ================================================
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SELECT '重新分析表...' AS info;
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ANALYZE TABLE sys_user;
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ANALYZE TABLE student_class;
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-- ================================================
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-- 5. 验证优化结果
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-- ================================================
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SELECT '优化完成，验证结果...' AS info;
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-- 查看 student_class 剩余索引
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SELECT '剩余索引 - student_class:' AS info;
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SELECT
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INDEX_NAME AS '索引名',
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GROUP_CONCAT(COLUMN_NAME ORDER BY SEQ_IN_INDEX) AS '列'
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FROM information_schema.STATISTICS
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WHERE TABLE_SCHEMA = 'study'
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AND TABLE_NAME = 'student_class'
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GROUP BY INDEX_NAME
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ORDER BY INDEX_NAME;
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-- 查看 sys_user 剩余索引
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SELECT '剩余索引 - sys_user:' AS info;
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SELECT
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INDEX_NAME AS '索引名',
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GROUP_CONCAT(COLUMN_NAME ORDER BY SEQ_IN_INDEX) AS '列'
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FROM information_schema.STATISTICS
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WHERE TABLE_SCHEMA = 'study'
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AND TABLE_NAME = 'sys_user'
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GROUP BY INDEX_NAME
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ORDER BY INDEX_NAME;
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-- 统计索引数量
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SELECT
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TABLE_NAME AS '表名',
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COUNT(DISTINCT INDEX_NAME) AS '索引数量'
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FROM information_schema.STATISTICS
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WHERE TABLE_SCHEMA = 'study'
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AND TABLE_NAME IN ('sys_user', 'student_class')
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GROUP BY TABLE_NAME;
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SELECT '冗余索引删除完成！系统速度应该恢复正常。' AS info;
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SELECT '如果需要保留某些索引，请手动添加回来。' AS info;
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