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How to get faster output on SQL query to join four tables

SQL query is joining four tables in a WHERE clause. Three tables are very small but one table has a very large number of rows (2.5 milion rows). The execution plan shows an index unique scan on small tables, and an index range scan on a large table. The query takes more than one hour to show the output. I need the output within 30 minutes.

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Are the join columns all indexed? Does the query specify the join correctly? Thirty minutes is excessive, even with a 2.5-million row table. You should experiment with the use of different indexes and with optimizer hints to force different join orders and join algorithms.

This was first published in October 2004

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