Create README.md

elinabel · web-flow · commit af56209c33f3 · 2024-08-22T15:42:58.000+03:00
diff --git a/Урок 10.3 Преобразования типов данных/README.md b/Урок 10.3 Преобразования типов данных/README.md
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+# Преобразования типов данных
+```sql
+select
+	f.rental_rate,
+	cast(f.rental_rate as varchar(10))
+from
+	film f;
+```
+```sql
+select
+	1 as filed1
+union all
+select
+	1.5 as filed1;
+```
+```sql
+with cte as (
+	select
+		1 as filed1
+union all
+	select
+		1.5 as filed1
+
+)
+
+select
+	filed1,
+	pg_typeof(filed1)
+from
+	cte;
+```
+```sql
+select
+	cast(1 as numeric) as filed1
+union all
+
+select
+	1.5 as filed1;
+```
+```sql
+select
+	1::numeric as filed1
+union all
+select
+	1.5 as filed1;
+```
+```sql
+with cte as (
+select
+	1 as filed1
+union all
+select
+	1 as filed1
+)
+select
+	filed1,
+	pg_typeof(filed1)
+from
+	cte;
+```
+```sql
+select
+	1 as filed1
+union all
+
+select
+	'2' as filed1;
+```
+```sql
+select
+	1 as filed1
+union all
+select
+	'some text' as filed1;
+```
+```sql
+select
+	cast(1 as varchar) as filed1
+union all
+select
+	'2' as filed1;
+```
+```sql
+select
+	1 as field1
+union all
+select
+	false as field1;
+```
+```sql
+select
+	now();
+```
+```sql
+select
+	to_char(now(), 'yyyy---mm---dd  hh:mi');
+```
+```sql
+select
+	to_char(now(), 'dd/mm/yyyy');
+```
+```sql
+select
+	to_char(now(), 'dd/mon/yyyy');
+```
+```sql
+select
+	to_char(now(), 'dd/month/yy hh24:mi:ss');
+```
+```sql
+select
+	cast('2021-10-01' as date);
+```
+```sql
+select
+	cast('01/10/2021 10:21' as timestamp);
+```
+```sql
+select
+	to_date('21/10/01', 'yy/mm/dd');
+```
+```sql
+select
+	to_timestamp('21/10/01 10:11', 'yy/mm/dd hh24:mi');
+```
