oceanbase

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drop table if exists tt1;
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create table tt1(c1 int primary key, c2 int);
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insert into tt1 values(1,4);
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insert into tt1 values(2,3);
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select c1, c2 as c1 from tt1;
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c1	c1
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1	4
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2	3
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select c1, c2 as c1 from tt1 order by c1;
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ERROR 23000: Column 'c1' in order clause is ambiguous
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select c2 as c1 from tt1 order by c1;
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c1
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3
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4
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select c2 as c1 from tt1 where c1<4;
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c1
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4
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3
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select c1 as cc, c2 as c1 from tt1 where c1<4;
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cc	c1
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1	4
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2	3
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select c1 as cc, c2 as c1 from tt1 order by c1;
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cc	c1
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2	3
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1	4
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select c1, c2 as c1 from tt1 where c1<4;
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c1	c1
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1	4
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2	3
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select c2 as cc from tt1  order by c1;
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cc
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4
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3
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select c2 as c1 from tt1 order by c1;
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c1
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3
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4
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select c1 as c1, c2 as c1 from tt1 where c1<4;
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c1	c1
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1	4
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2	3
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show columns from tt1;
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Field	Type	Null	Key	Default	Extra
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c1	int(11)	NO	PRI	NULL	
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c2	int(11)	YES		NULL	
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