Merge pull request #254 from GeoSegun/new-branch

How to Check Indexes on a Table in SQL

Author: maibin

sql-queries-6/check-indexes-in-sql/using-SHOW-INDEX-mysql.sql

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+SHOW INDEX FROM Student;

sql-queries-6/check-indexes-in-sql/using-di-command-pg.sql

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+\di

sql-queries-6/check-indexes-in-sql/using-information_schema.STATISTICS-mysql.sql

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+SELECT INDEX_NAME, COLUMN_NAME, SEQ_IN_INDEX, NON_UNIQUE, INDEX_TYPE 
+FROM information_schema.STATISTICS 
+WHERE TABLE_SCHEMA = 'University' AND TABLE_NAME = 'Exam';

sql-queries-6/check-indexes-in-sql/using-pg_catalog.pg_index-system-table.sql

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+SELECT i.indexrelid::regclass AS index_name, 
+       array_to_string(array_agg(a.attname), ', ') AS index_columns
+FROM pg_index i
+JOIN pg_attribute a ON a.attnum = ANY(i.indkey)
+WHERE i.indrelid = 'course'::regclass
+GROUP BY i.indexrelid;

sql-queries-6/check-indexes-in-sql/using-pg_indexes-system-catalog-pg.sql

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+SELECT indexname, indexdef 
+FROM pg_indexes 
+WHERE tablename = 'student';

sql-queries-6/check-indexes-in-sql/using-sp_helpindex-sqlserver.sql

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+EXEC sp_helpindex 'Student';

sql-queries-6/check-indexes-in-sql/using-sys.index_columns.sql

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+SELECT i.name AS index_name, c.name AS column_name, ic.index_column_id
+FROM sys.indexes i
+JOIN sys.index_columns ic ON i.object_id = ic.object_id AND i.index_id = ic.index_id
+JOIN sys.columns c ON ic.object_id = c.object_id AND ic.column_id = c.column_id
+WHERE i.object_id = OBJECT_ID('Student');

sql-queries-6/check-indexes-in-sql/using-sys.indexes-sqlserver.sql

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+SELECT name AS index_name, type_desc, is_unique, is_primary_key 
+FROM sys.indexes 
+WHERE object_id = OBJECT_ID('Course')