1、查看指定的数据库是否存在
SELECT information_schema.SCHEMATA.SCHEMA_NAME FROM information_schema.SCHEMATA where SCHEMA_NAME='databaseName';
2、查看指定的数据库下是否存在某张表
SELECT DISTINCT t.table_name, n.SCHEMA_NAME FROM information_schema.TABLES t, information_schema.SCHEMATA n WHERE t.
table_name = 'tableName' AND n.SCHEMA_NAME = 'databaseName';










