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Introduce TRIM/LTRIM/RTRIM functions #3714

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This commit is contained in:
Ivan Blinkov 2018-12-13 14:50:37 +03:00
parent 3209ac84d0
commit 034265f044
4 changed files with 166 additions and 0 deletions
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149
dbms/src/Parsers/ExpressionElementParsers.cpp
View File

@ -388,6 +388,154 @@ bool ParserSubstringExpression::parseImpl(Pos & pos, ASTPtr & node, Expected & e
return true;
}
bool ParserTrimExpression::parseImpl(Pos & pos, ASTPtr & node, Expected & expected)
{
/// Handles all possible TRIM/LTRIM/RTRIM call variants
std::string func_name = "replaceRegexpOne";
bool trim_left = false;
bool trim_right = false;
bool char_override = false;
ASTPtr expr_node;
ASTPtr pattern_node;
ASTPtr to_remove;
if (ParserKeyword("LTRIM").ignore(pos, expected))
{
if (pos->type != TokenType::OpeningRoundBracket)
return false;
++pos;
trim_left = true;
}
else if (ParserKeyword("RTRIM").ignore(pos, expected))
{
if (pos->type != TokenType::OpeningRoundBracket)
return false;
++pos;
trim_right = true;
}
else if (ParserKeyword("TRIM").ignore(pos, expected))
{
if (pos->type != TokenType::OpeningRoundBracket)
return false;
++pos;
if (ParserKeyword("BOTH").ignore(pos, expected))
{
trim_left = true;
trim_right = true;
char_override = true;
}
else if (ParserKeyword("LEADING").ignore(pos, expected))
{
trim_left = true;
char_override = true;
}
else if (ParserKeyword("TRAILING").ignore(pos, expected))
{
trim_right = true;
char_override = true;
}
else
{
trim_left = true;
trim_right = true;
}
if (char_override)
{
if (!ParserExpression().parse(pos, to_remove, expected)) /// TODO: wrap in RE2::QuoteMeta call
return false;
if (!ParserKeyword("FROM").ignore(pos, expected))
return false;
}
}
if (!(trim_left || trim_right))
return false;
if (!ParserExpression().parse(pos, expr_node, expected))
return false;
if (pos->type != TokenType::ClosingRoundBracket)
return false;
++pos;
/// Convert to regexp replace function call
auto pattern_func_node = std::make_shared<ASTFunction>();
if (char_override)
{
auto pattern_list_args = std::make_shared<ASTExpressionList>();
if (trim_left && trim_right)
{
pattern_list_args->children = {
std::make_shared<ASTLiteral>("^["),
to_remove,
std::make_shared<ASTLiteral>("]*|["),
to_remove,
std::make_shared<ASTLiteral>("]*$")
};
func_name = "replaceRegexpAll";
}
else {
if (trim_left)
{
pattern_list_args->children = {
std::make_shared<ASTLiteral>("^["),
to_remove,
std::make_shared<ASTLiteral>("]*")
};
}
else
{
/// trim_right == false not possible
pattern_list_args->children = {
std::make_shared<ASTLiteral>("["),
to_remove,
std::make_shared<ASTLiteral>("]*$")
};
}
}
pattern_func_node->name = "concat";
pattern_func_node->arguments = std::move(pattern_list_args);
pattern_func_node->children.push_back(pattern_func_node->arguments);
pattern_node = std::move(pattern_func_node);
}
else
{
if (trim_left && trim_right)
{
pattern_node = std::make_shared<ASTLiteral>("^ *\\| *$");
func_name = "replaceRegexpAll";
}
else {
if (trim_left)
{
pattern_node = std::make_shared<ASTLiteral>("^ *");
}
else
{
/// trim_right == false not possible
pattern_node = std::make_shared<ASTLiteral>(" *$");
}
}
}
auto expr_list_args = std::make_shared<ASTExpressionList>();
expr_list_args->children = {expr_node, pattern_node, std::make_shared<ASTLiteral>("")};
auto func_node = std::make_shared<ASTFunction>();
func_node->name = func_name;
func_node->arguments = std::move(expr_list_args);
func_node->children.push_back(func_node->arguments);
node = std::move(func_node);
return true;
}
bool ParserLeftExpression::parseImpl(Pos & pos, ASTPtr & node, Expected & expected)
{
/// Rewrites left(expr, length) to SUBSTRING(expr, 1, length)
@ -861,6 +1009,7 @@ bool ParserExpressionElement::parseImpl(Pos & pos, ASTPtr & node, Expected & exp
|| ParserCastExpression().parse(pos, node, expected)
|| ParserExtractExpression().parse(pos, node, expected)
|| ParserSubstringExpression().parse(pos, node, expected)
|| ParserTrimExpression().parse(pos, node, expected)
|| ParserLeftExpression().parse(pos, node, expected)
|| ParserRightExpression().parse(pos, node, expected)
|| ParserCase().parse(pos, node, expected)

7
dbms/src/Parsers/ExpressionElementParsers.h
View File

@ -103,6 +103,13 @@ protected:
bool parseImpl(Pos & pos, ASTPtr & node, Expected & expected) override;
};
class ParserTrimExpression : public IParserBase
{
protected:
const char * getName() const override { return "TRIM expression"; }
bool parseImpl(Pos & pos, ASTPtr & node, Expected & expected) override;
};
class ParserLeftExpression : public IParserBase
{
protected:

5
dbms/tests/queries/0_stateless/00765_sql_compatibility_aliases.reference
View File

@ -12,3 +12,8 @@ oo
o
fo
r
foo
foo
xxfoo
fooabba
fooabbafoo

5
dbms/tests/queries/0_stateless/00765_sql_compatibility_aliases.sql
View File

@ -14,3 +14,8 @@ select substring('foo' from 1 + 1);
select SUBSTRING('foo' FROM 2 FOR 1);
select left('foo', 2);
select RIGHT('bar', 1);
select ltrim(' foo');
select RTRIM(' foo ');
select trim(TRAILING 'x' FROM 'xxfooxx');
select Trim(LEADING 'ab' FROM 'abbafooabba');
select TRIM(both 'ab' FROM 'abbafooabbafooabba');