java.lang.Object
- com.exasol.adapter.dialects.rewriting.SqlGenerationVisitor

All Implemented Interfaces:

SqlGenerator, com.exasol.adapter.sql.SqlNodeVisitor<String>
```
public class SqlGenerationVisitor
extends Object
implements com.exasol.adapter.sql.SqlNodeVisitor<String>, SqlGenerator
```
This class has the logic to generate SQL queries based on a graph of SqlNode elements. It uses the visitor pattern. This class interacts with the dialects in some situations, e.g. to find out how to handle quoting, case-sensitivity.
If this class is not sufficiently customizable for your use case, you can extend this class and override the required methods. You also have to return your custom visitor class then in the method SqlDialect.getSqlGenerator(SqlGenerationContext).
Note on operator associativity and parenthesis generation: Currently we almost always use parenthesis. Without parenthesis, two SqlNode graphs with different semantic lead to select 1 = 1 - 1 + 1. Also SELECT NOT NOT TRUE needs to be written as SELECT NOT (NOT TRUE) to work at all, whereas SELECT NOT TRUE works fine without parentheses. Currently we make inflationary use of parenthesis to enforce the right semantic, but hopefully there is a better way.

Constructor Summary

Constructors
Constructor Description

SqlGenerationVisitor(SqlDialect dialect, SqlGenerationContext context)
Creates a new instance of the SqlGenerationVisitor.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`protected void`	`checkDialectAliases()`	Check if dialect provided invalid aliases, which would never be applied.
`protected String`	`createExplicitColumnsSelectList(com.exasol.adapter.sql.SqlSelectList selectList)`	Create a list of explicitly specified columns (where columns can also be expressions) for a `SELECT` list.
`String`	`generateSqlFor(com.exasol.adapter.sql.SqlNode sqlNode)`	Generate a SQL representation of the pass `SqlNode`.
`protected SqlDialect`	`getDialect()`	Get the SQL dialect.
`protected String`	`getTypeNameFromColumn(com.exasol.adapter.sql.SqlColumn column)`	Get the type name for a column
`protected boolean`	`isDirectlyInSelectList(com.exasol.adapter.sql.SqlColumn column)`	Check if a column is directly in the select list.
`protected String`	`representAnyColumnInSelectList()`	Represent "any column" in the `SELECT` list.
`String`	`visit(com.exasol.adapter.sql.SqlColumn column)`
`String`	`visit(com.exasol.adapter.sql.SqlFunctionAggregate function)`
`String`	`visit(com.exasol.adapter.sql.SqlFunctionAggregateGroupConcat function)`
`String`	`visit(com.exasol.adapter.sql.SqlFunctionAggregateListagg sqlFunctionAggregateListagg)`
`String`	`visit(com.exasol.adapter.sql.SqlFunctionScalar function)`
`String`	`visit(com.exasol.adapter.sql.SqlFunctionScalarCase function)`
`String`	`visit(com.exasol.adapter.sql.SqlFunctionScalarCast function)`
`String`	`visit(com.exasol.adapter.sql.SqlFunctionScalarExtract function)`
`String`	`visit(com.exasol.adapter.sql.SqlFunctionScalarJsonValue function)`
`String`	`visit(com.exasol.adapter.sql.SqlGroupBy groupBy)`
`String`	`visit(com.exasol.adapter.sql.SqlJoin join)`
`String`	`visit(com.exasol.adapter.sql.SqlLimit limit)`
`String`	`visit(com.exasol.adapter.sql.SqlLiteralBool literal)`
`String`	`visit(com.exasol.adapter.sql.SqlLiteralDate literal)`
`String`	`visit(com.exasol.adapter.sql.SqlLiteralDouble literal)`	Get a value of the double converted to an E-notation format.
`String`	`visit(com.exasol.adapter.sql.SqlLiteralExactnumeric literal)`	Formats a value of the exactnumeric as a plain string without E notation.
`String`	`visit(com.exasol.adapter.sql.SqlLiteralInterval literal)`
`String`	`visit(com.exasol.adapter.sql.SqlLiteralNull literal)`
`String`	`visit(com.exasol.adapter.sql.SqlLiteralString literal)`
`String`	`visit(com.exasol.adapter.sql.SqlLiteralTimestamp literal)`
`String`	`visit(com.exasol.adapter.sql.SqlLiteralTimestampUtc literal)`
`String`	`visit(com.exasol.adapter.sql.SqlOrderBy orderBy)`
`String`	`visit(com.exasol.adapter.sql.SqlPredicateAnd predicate)`
`String`	`visit(com.exasol.adapter.sql.SqlPredicateBetween predicate)`
`String`	`visit(com.exasol.adapter.sql.SqlPredicateEqual predicate)`
`String`	`visit(com.exasol.adapter.sql.SqlPredicateInConstList predicate)`
`String`	`visit(com.exasol.adapter.sql.SqlPredicateIsJson function)`
`String`	`visit(com.exasol.adapter.sql.SqlPredicateIsNotJson function)`
`String`	`visit(com.exasol.adapter.sql.SqlPredicateIsNotNull predicate)`
`String`	`visit(com.exasol.adapter.sql.SqlPredicateIsNull predicate)`
`String`	`visit(com.exasol.adapter.sql.SqlPredicateLess predicate)`
`String`	`visit(com.exasol.adapter.sql.SqlPredicateLessEqual predicate)`
`String`	`visit(com.exasol.adapter.sql.SqlPredicateLike predicate)`
`String`	`visit(com.exasol.adapter.sql.SqlPredicateLikeRegexp predicate)`
`String`	`visit(com.exasol.adapter.sql.SqlPredicateNot predicate)`
`String`	`visit(com.exasol.adapter.sql.SqlPredicateNotEqual predicate)`
`String`	`visit(com.exasol.adapter.sql.SqlPredicateOr predicate)`
`String`	`visit(com.exasol.adapter.sql.SqlSelectList selectList)`
`String`	`visit(com.exasol.adapter.sql.SqlStatementSelect select)`
`String`	`visit(com.exasol.adapter.sql.SqlTable table)`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - SqlGenerationVisitor
```
public SqlGenerationVisitor(SqlDialect dialect,
                            SqlGenerationContext context)
```
    Creates a new instance of the SqlGenerationVisitor.
    
    Parameters:
    
    dialect - SQl dialect
    
    context - SQL generation context
- Method Detail
  - generateSqlFor
```
public String generateSqlFor(com.exasol.adapter.sql.SqlNode sqlNode)
                      throws com.exasol.adapter.AdapterException
```
    Description copied from interface: SqlGenerator
    
    Generate a SQL representation of the pass SqlNode.
    
    Specified by:
    
    generateSqlFor in interface SqlGenerator
    
    Parameters:
    
    sqlNode - sqlNode
    
    Returns:
    
    SQL representation
    
    Throws:
    
    com.exasol.adapter.AdapterException - if an error occurs while generating the SQL representation.
  - getDialect
```
protected SqlDialect getDialect()
```
    Get the SQL dialect.
    
    Returns:
    
    SQL dialect.
  - checkDialectAliases
```
protected void checkDialectAliases()
```
    Check if dialect provided invalid aliases, which would never be applied.
  - isDirectlyInSelectList
```
protected boolean isDirectlyInSelectList(com.exasol.adapter.sql.SqlColumn column)
```
    Check if a column is directly in the select list.
    
    Parameters:
    
    column - column name
    
    Returns:
    
    true if the column is directly in the select list of a query
  - visit
```
public String visit(com.exasol.adapter.sql.SqlStatementSelect select)
             throws com.exasol.adapter.AdapterException
```
    Specified by:
    
    visit in interface com.exasol.adapter.sql.SqlNodeVisitor<String>
    
    Throws:
    
    com.exasol.adapter.AdapterException
  - visit
```
public String visit(com.exasol.adapter.sql.SqlSelectList selectList)
             throws com.exasol.adapter.AdapterException
```
    Specified by:
    
    visit in interface com.exasol.adapter.sql.SqlNodeVisitor<String>
    
    Throws:
    
    com.exasol.adapter.AdapterException
  - representAnyColumnInSelectList
```
protected String representAnyColumnInSelectList()
```
    Represent "any column" in the SELECT list.
    A typical example are queries where the only thing that matters if what you searched for exists or not. Different databases have different preferred ways of expressing this kind of result.
    
    Returns:
    
    always "true"
  - createExplicitColumnsSelectList
```
protected String createExplicitColumnsSelectList(com.exasol.adapter.sql.SqlSelectList selectList)
                                          throws com.exasol.adapter.AdapterException
```
    Create a list of explicitly specified columns (where columns can also be expressions) for a SELECT list.
    
    Parameters:
    
    selectList - list of columns (or expressions) in the SELECT part
    
    Returns:
    
    string representing the SELECT list
    
    Throws:
    
    com.exasol.adapter.AdapterException - in case the expressions in the list cannot be rendered to SQL
  - visit
```
public String visit(com.exasol.adapter.sql.SqlColumn column)
             throws com.exasol.adapter.AdapterException
```
    Specified by:
    
    visit in interface com.exasol.adapter.sql.SqlNodeVisitor<String>
    
    Throws:
    
    com.exasol.adapter.AdapterException
  - visit
```
public String visit(com.exasol.adapter.sql.SqlTable table)
```
    Specified by:
    
    visit in interface com.exasol.adapter.sql.SqlNodeVisitor<String>
  - visit
```
public String visit(com.exasol.adapter.sql.SqlJoin join)
             throws com.exasol.adapter.AdapterException
```
    Specified by:
    
    visit in interface com.exasol.adapter.sql.SqlNodeVisitor<String>
    
    Throws:
    
    com.exasol.adapter.AdapterException
  - visit
```
public String visit(com.exasol.adapter.sql.SqlFunctionAggregateListagg sqlFunctionAggregateListagg)
             throws com.exasol.adapter.AdapterException
```
    Specified by:
    
    visit in interface com.exasol.adapter.sql.SqlNodeVisitor<String>
    
    Throws:
    
    com.exasol.adapter.AdapterException
  - visit
```
public String visit(com.exasol.adapter.sql.SqlGroupBy groupBy)
             throws com.exasol.adapter.AdapterException
```
    Specified by:
    
    visit in interface com.exasol.adapter.sql.SqlNodeVisitor<String>
    
    Throws:
    
    com.exasol.adapter.AdapterException
  - visit
```
public String visit(com.exasol.adapter.sql.SqlFunctionAggregate function)
             throws com.exasol.adapter.AdapterException
```
    Specified by:
    
    visit in interface com.exasol.adapter.sql.SqlNodeVisitor<String>
    
    Throws:
    
    com.exasol.adapter.AdapterException
  - visit
```
public String visit(com.exasol.adapter.sql.SqlFunctionAggregateGroupConcat function)
             throws com.exasol.adapter.AdapterException
```
    Specified by:
    
    visit in interface com.exasol.adapter.sql.SqlNodeVisitor<String>
    
    Throws:
    
    com.exasol.adapter.AdapterException
  - visit
```
public String visit(com.exasol.adapter.sql.SqlFunctionScalar function)
             throws com.exasol.adapter.AdapterException
```
    Specified by:
    
    visit in interface com.exasol.adapter.sql.SqlNodeVisitor<String>
    
    Throws:
    
    com.exasol.adapter.AdapterException
  - visit
```
public String visit(com.exasol.adapter.sql.SqlFunctionScalarCase function)
             throws com.exasol.adapter.AdapterException
```
    Specified by:
    
    visit in interface com.exasol.adapter.sql.SqlNodeVisitor<String>
    
    Throws:
    
    com.exasol.adapter.AdapterException
  - visit
```
public String visit(com.exasol.adapter.sql.SqlFunctionScalarCast function)
             throws com.exasol.adapter.AdapterException
```
    Specified by:
    
    visit in interface com.exasol.adapter.sql.SqlNodeVisitor<String>
    
    Throws:
    
    com.exasol.adapter.AdapterException
  - visit
```
public String visit(com.exasol.adapter.sql.SqlFunctionScalarExtract function)
             throws com.exasol.adapter.AdapterException
```
    Specified by:
    
    visit in interface com.exasol.adapter.sql.SqlNodeVisitor<String>
    
    Throws:
    
    com.exasol.adapter.AdapterException
  - visit
```
public String visit(com.exasol.adapter.sql.SqlFunctionScalarJsonValue function)
             throws com.exasol.adapter.AdapterException
```
    Specified by:
    
    visit in interface com.exasol.adapter.sql.SqlNodeVisitor<String>
    
    Throws:
    
    com.exasol.adapter.AdapterException
  - visit
```
public String visit(com.exasol.adapter.sql.SqlLimit limit)
```
    Specified by:
    
    visit in interface com.exasol.adapter.sql.SqlNodeVisitor<String>
  - visit
```
public String visit(com.exasol.adapter.sql.SqlLiteralBool literal)
```
    Specified by:
    
    visit in interface com.exasol.adapter.sql.SqlNodeVisitor<String>
  - visit
```
public String visit(com.exasol.adapter.sql.SqlLiteralDate literal)
```
    Specified by:
    
    visit in interface com.exasol.adapter.sql.SqlNodeVisitor<String>
  - visit
```
public String visit(com.exasol.adapter.sql.SqlLiteralDouble literal)
```
    Get a value of the double converted to an E-notation format.
    For example: 1.234 becomes 1.234E0
    
    Specified by:
    
    visit in interface com.exasol.adapter.sql.SqlNodeVisitor<String>
  - visit
```
public String visit(com.exasol.adapter.sql.SqlLiteralExactnumeric literal)
```
    Formats a value of the exactnumeric as a plain string without E notation.
    For example: 1E-35 becomes 0.00000000000000000000000000000000001
    
    Specified by:
    
    visit in interface com.exasol.adapter.sql.SqlNodeVisitor<String>
  - visit
```
public String visit(com.exasol.adapter.sql.SqlLiteralNull literal)
```
    Specified by:
    
    visit in interface com.exasol.adapter.sql.SqlNodeVisitor<String>
  - visit
```
public String visit(com.exasol.adapter.sql.SqlLiteralString literal)
```
    Specified by:
    
    visit in interface com.exasol.adapter.sql.SqlNodeVisitor<String>
  - visit
```
public String visit(com.exasol.adapter.sql.SqlLiteralTimestamp literal)
```
    Specified by:
    
    visit in interface com.exasol.adapter.sql.SqlNodeVisitor<String>
  - visit
```
public String visit(com.exasol.adapter.sql.SqlLiteralTimestampUtc literal)
```
    Specified by:
    
    visit in interface com.exasol.adapter.sql.SqlNodeVisitor<String>
  - visit
```
public String visit(com.exasol.adapter.sql.SqlLiteralInterval literal)
```
    Specified by:
    
    visit in interface com.exasol.adapter.sql.SqlNodeVisitor<String>
  - visit
```
public String visit(com.exasol.adapter.sql.SqlOrderBy orderBy)
             throws com.exasol.adapter.AdapterException
```
    Specified by:
    
    visit in interface com.exasol.adapter.sql.SqlNodeVisitor<String>
    
    Throws:
    
    com.exasol.adapter.AdapterException
  - visit
```
public String visit(com.exasol.adapter.sql.SqlPredicateAnd predicate)
             throws com.exasol.adapter.AdapterException
```
    Specified by:
    
    visit in interface com.exasol.adapter.sql.SqlNodeVisitor<String>
    
    Throws:
    
    com.exasol.adapter.AdapterException
  - visit
```
public String visit(com.exasol.adapter.sql.SqlPredicateBetween predicate)
             throws com.exasol.adapter.AdapterException
```
    Specified by:
    
    visit in interface com.exasol.adapter.sql.SqlNodeVisitor<String>
    
    Throws:
    
    com.exasol.adapter.AdapterException
  - visit
```
public String visit(com.exasol.adapter.sql.SqlPredicateEqual predicate)
             throws com.exasol.adapter.AdapterException
```
    Specified by:
    
    visit in interface com.exasol.adapter.sql.SqlNodeVisitor<String>
    
    Throws:
    
    com.exasol.adapter.AdapterException
  - visit
```
public String visit(com.exasol.adapter.sql.SqlPredicateInConstList predicate)
             throws com.exasol.adapter.AdapterException
```
    Specified by:
    
    visit in interface com.exasol.adapter.sql.SqlNodeVisitor<String>
    
    Throws:
    
    com.exasol.adapter.AdapterException
  - visit
```
public String visit(com.exasol.adapter.sql.SqlPredicateIsJson function)
             throws com.exasol.adapter.AdapterException
```
    Specified by:
    
    visit in interface com.exasol.adapter.sql.SqlNodeVisitor<String>
    
    Throws:
    
    com.exasol.adapter.AdapterException
  - visit
```
public String visit(com.exasol.adapter.sql.SqlPredicateIsNotJson function)
             throws com.exasol.adapter.AdapterException
```
    Specified by:
    
    visit in interface com.exasol.adapter.sql.SqlNodeVisitor<String>
    
    Throws:
    
    com.exasol.adapter.AdapterException
  - visit
```
public String visit(com.exasol.adapter.sql.SqlPredicateLess predicate)
             throws com.exasol.adapter.AdapterException
```
    Specified by:
    
    visit in interface com.exasol.adapter.sql.SqlNodeVisitor<String>
    
    Throws:
    
    com.exasol.adapter.AdapterException
  - visit
```
public String visit(com.exasol.adapter.sql.SqlPredicateLessEqual predicate)
             throws com.exasol.adapter.AdapterException
```
    Specified by:
    
    visit in interface com.exasol.adapter.sql.SqlNodeVisitor<String>
    
    Throws:
    
    com.exasol.adapter.AdapterException
  - visit
```
public String visit(com.exasol.adapter.sql.SqlPredicateLike predicate)
             throws com.exasol.adapter.AdapterException
```
    Specified by:
    
    visit in interface com.exasol.adapter.sql.SqlNodeVisitor<String>
    
    Throws:
    
    com.exasol.adapter.AdapterException
  - visit
```
public String visit(com.exasol.adapter.sql.SqlPredicateLikeRegexp predicate)
             throws com.exasol.adapter.AdapterException
```
    Specified by:
    
    visit in interface com.exasol.adapter.sql.SqlNodeVisitor<String>
    
    Throws:
    
    com.exasol.adapter.AdapterException
  - visit
```
public String visit(com.exasol.adapter.sql.SqlPredicateNot predicate)
             throws com.exasol.adapter.AdapterException
```
    Specified by:
    
    visit in interface com.exasol.adapter.sql.SqlNodeVisitor<String>
    
    Throws:
    
    com.exasol.adapter.AdapterException
  - visit
```
public String visit(com.exasol.adapter.sql.SqlPredicateNotEqual predicate)
             throws com.exasol.adapter.AdapterException
```
    Specified by:
    
    visit in interface com.exasol.adapter.sql.SqlNodeVisitor<String>
    
    Throws:
    
    com.exasol.adapter.AdapterException
  - visit
```
public String visit(com.exasol.adapter.sql.SqlPredicateOr predicate)
             throws com.exasol.adapter.AdapterException
```
    Specified by:
    
    visit in interface com.exasol.adapter.sql.SqlNodeVisitor<String>
    
    Throws:
    
    com.exasol.adapter.AdapterException
  - visit
```
public String visit(com.exasol.adapter.sql.SqlPredicateIsNull predicate)
             throws com.exasol.adapter.AdapterException
```
    Specified by:
    
    visit in interface com.exasol.adapter.sql.SqlNodeVisitor<String>
    
    Throws:
    
    com.exasol.adapter.AdapterException
  - visit
```
public String visit(com.exasol.adapter.sql.SqlPredicateIsNotNull predicate)
             throws com.exasol.adapter.AdapterException
```
    Specified by:
    
    visit in interface com.exasol.adapter.sql.SqlNodeVisitor<String>
    
    Throws:
    
    com.exasol.adapter.AdapterException
  - getTypeNameFromColumn
```
protected String getTypeNameFromColumn(com.exasol.adapter.sql.SqlColumn column)
                                throws com.exasol.adapter.AdapterException
```
    Get the type name for a column
    
    Parameters:
    
    column - column
    
    Returns:
    
    type name
    
    Throws:
    
    com.exasol.adapter.AdapterException - if something goes wrong

Class SqlGenerationVisitor

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

SqlGenerationVisitor

Method Detail

generateSqlFor

getDialect

checkDialectAliases

isDirectlyInSelectList

visit

visit

representAnyColumnInSelectList

createExplicitColumnsSelectList

visit

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getTypeNameFromColumn