26 lines
405 B
Markdown
26 lines
405 B
Markdown
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# Fonctions
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```sql
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insert into exchange_rate values
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('EUR', '1999-01-04', 1),
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('USD', '1999-01-04', 1.1789),
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('YEN', '1999-01-04', 133.73);
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```
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```sql
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create or replace function latest_exchange_rate (
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p_code text,
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p_date date
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)
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returns decimal
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language sql
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as $$
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select rate
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from exchange_rate
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where currency_code = p_code
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and date < p_date
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order by date desc
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limit 1;
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$$;
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```
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