MySQL元数据操作:查询 MySQL 空表,拥有某字段的表,等
作者:互联网
1、查询MySQL库下所有表名,数据为空的表
SELECT table_name, table_rows FROM information_schema. TABLES WHERE table_schema = 'ahbo' AND table_rows < 1;
2、查询指定库拥有某字段的表
SELECT DISTINCT TABLE_NAME FROM information_schema. COLUMNS WHERE COLUMN_NAME = 'columnName' AND TABLE_SCHEMA = 'dbName' AND TABLE_NAME NOT LIKE 'vw%';
3、修改指定数据库中所有varchar类型的表字段的字符集为UTF8,并将排序规则修改为utf8_general_ci
SELECT CONCAT('ALTER TABLE `', table_name, '` MODIFY `', column_name, '` ', DATA_TYPE, '(', CHARACTER_MAXIMUM_LENGTH, ') CHARACTER SET UTF8 COLLATE utf8_general_ci', (CASE WHEN IS_NULLABLE = 'NO' THEN ' NOT NULL' ELSE '' END), ';') 别名 FROM information_schema.COLUMNS WHERE TABLE_SCHEMA = 'SchoolUserOnline_20170416' AND DATA_TYPE = 'varchar' AND ( CHARACTER_SET_NAME != 'utf8' OR COLLATION_NAME != 'utf8_general_ci' );
4、修改指定数据库中所有数据表的字符集为UTF8,并将排序规则修改为utf8_general_ci
SELECT CONCAT('ALTER TABLE ', table_name, ' CONVERT TO CHARACTER SET utf8 COLLATE utf8_unicode_ci;') FROM information_schema.TABLES WHERE TABLE_SCHEMA = 'databaseName'
标签:ci,空表,某字,NAME,utf8,MySQL,table,TABLE,schema 来源: https://www.cnblogs.com/erlongxizhu-03/p/14299368.html