Databases

To get the number of rows in all tables in MySQL database, use this query. SELECT table_name, table_rows FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = 'databaseName;

To identify the duplicate entries in MySQL, use below query.                      SELECT COUNT(*) as repetitions, group_concat(id, ' (', startTime, ', ', endTime, ') ' SEPARATOR ' | ') as row_data FROM GROUP BY startTime, endTime HAVING repetitions > 1 FYI, id, startTime and endTime columns should be changed based on your table schema. you can change the output format here like alias and the separator.

To get all the Foreign key referenced table and its column, use below query in MySQL.             select table_name, column_name, constraint_name, referenced_table_name, referenced_column_name from information_schema.key_column_usage where referenced_table_schema = 'dbName' and referenced_table_name = 'tableName' and referenced_column_name = 'columnName';

To rename the database is MSSQL, use below queries. ALTER DATABASE srcDatabaseName SET SINGLE_USER WITH ROLLBACK IMMEDIATE; GO sp_rename ' srcDatabaseName' , ' dest DatabaseName ' ,'DATABASE'; GO ALTER DATABASE dest DatabaseName SET MULTI_USER;

Let's say the user's password expired and locked it in Oracle. To unlock the users, use below commands. sqlplus "/as sysdba" alter user userName identified by password; alter user userName account unlock;

To get all indexes in SQL Server, use below query. SELECT TableName = t.name, IndexName = ind.name, IndexId = ind.index_id, ColumnId = ic.index_column_id, ColumnName = col.name, ind.*, ic.*, col.* FROM sys.indexes ind INNER JOIN sys.index_columns ic ON  ind.object_id = ic.object_id and ind.index_id = ic.index_id INNER JOIN sys.columns col ON ic.object_id = col.object_id and ic.column_id = col.column_id INNER JOIN sys.tables t ON ind.object_id = t.object_id WHERE ind.is_primary_key = 0 AND t.is_ms_shipped = 0 ORDER BY t.name, ind.name, ind.index_id, ic.index_column_id;

There is no query to get the description of the table like in MySQL. Use  sp_columns stored procedure to describe the table in SQL Server.            exec sp_columns tableName; And also we can use sp_help to describe the table. sp_help is returned depend on whether name is specified, when it is specified, and what database object it is.            exec sp_help tableName;