Common Database queries (determining whether tables and fields exist)

Table_name and column_name are both uppercase: 1. MSSQLServer table: selectcount (*) fromdbo. sysobjectswherenametable_name; field: selectcount (*) fromsyscolumnswherecolumn_name; 2. MySQL table: sel

The table_name and column_name parameters are both uppercase: 1. MSSQL Server table: select count (*) from dbo. sysobjects where name = 'table _ name'; field: select count (*) from syscolumns where id = object_id ('table _ name') and name = 'column _ name '; 2. My SQL table: sel

The values of table_name and column_name are uppercase:

1. MSSQL Server

Table: select count (*) from dbo. sysobjects where name = 'table _ name ';
Field: select count (*) from syscolumns where id = object_id ('table _ name') and name = 'column _ name ';

2. My SQL

Table: select count (*) from information_schema.tables where table_name = 'table _ name ';
Field: select count (*) from information_schema.columns where table_name = 'table _ name' and column_name = 'column _ name ';

3. Oracle

Table: select count (*) from user_objects where object_name = 'table _ name ';
Field: select count (*) from user_tab_columns where table_name = 'table _ name' and column_name = 'column _ name ';

4. PostgreSql

Table: select count (*) from information_schema.tables where table_schema = 'table _ scheme' and table_name = 'table _ name ';
Field: select count (*) from information_schema.columns where table_schema = 'table _ scheme' and table_name = 'table _ name' and column_name = 'column _ name ';