176 lines
4.2 KiB
Markdown
176 lines
4.2 KiB
Markdown
# Overview
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This page has more details on the supported SQL in simple-sql-parser.
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See the [simple-sql-parser test cases](test_cases.html) page for
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examples.
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The target dialect of SQL at this time is ISO/ANSI SQL:2011. The
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parser supports queries, DDL, non-query DML, access control and
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transaction management syntax. The parser and syntax does not follow
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the standard grammar closely - they permit a lot of things which the
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grammar in the standard forbids. The intended usage is that an
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additional pass over the ast can be made if you want to carefully
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prohibit everything that the standard doesn't allow.
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Apart from this permissiveness, some work has been put into trying to
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get good parser error messages.
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# Queries
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## Select lists
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Supports scalar expressions, aliases with optional 'as'.
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## Set quantifiers on select
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Supports 'select distinct' and explicit 'select all'.
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## From clause
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* aliases
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* subqueries
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* functions
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* joins
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- natural
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- inner
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- left/right/full outer
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- cross
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- on expressions
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- using lists
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- lateral
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## Group by clause
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Supports scalar expressions, group by (), cube, rollup, grouping
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parentheses and grouping sets with nested grouping expressions.
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## Order by clause
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Supports scalar expressions, asc/desc and nulls first/last.
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## Offset and fetch
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Supports 'offset n rows' and 'fetch first n rows only'.
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## Set operators
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Union, except, intersect + all/distinct and corresponding.
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## Table value constructor
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Example: 'values (1,2),(3,4)'.
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## Explicit table
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Example: 'table t', which is shorthand for 'select * from t'.
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## Scalar expressions
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The scalar expressions type and parser is used in many contexts,
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including:
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* select lists;
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* where clause expressions;
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* group by clause expressions;
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* having clause expressions;
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* order by clause expressions;
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* offset and fetch clause expressions;
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* table value constructors.
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This doesn't exactly follow the ANSI Standards, which have separate
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grammars for most of these.
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The supported scalar expressions include:
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* basic string literals in single quotes
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* number literals: digits.digitse+-exp
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* explicitly typed literal, e.g. int '3'
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* binary operators
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- comparisons: = != <> <= >= < >
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- arithmetic: + - / * % ^
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- logic: and, or
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- bitwise: & | (and ^ as above)
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- string: ||, like, not like
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- other: overlaps, is similar to, is not similar too, is distinct
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from, is not distinct from
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* prefix unary operators
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- +, -
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- not
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- ~
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* postfix unary
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- is null, is not null
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- is true, is not true, is false, is not false, is unknown, is not unknown
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* other operators
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- extract (extract(day from dt))
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- position (position string1 in string2)
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- substring (substring(x from 2 for 4))
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- convert (convert(string using conversion))
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- translate (translate(string using translation))
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- overlay (overlay (string placing embedded_string from start for
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length))
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- trim (trim(leading '_' from s))
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- between (a between 1 and 5)
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- in list (a in (1,2,3,4))
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- cast (cast(a as int))
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* subqueries
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- in subquery
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- any/some/all
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- exists
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* case expressions
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* parentheses
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* quoted and unquoted identifiers
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* a.b qualified identifiers
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* \*, a.*
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* functions: f(a,b)
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* aggregates: agg(distinct a order by b)
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* window functions: sum(x) over (partition by y order by z)
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plus some explicit frame support (same as in postgres 9.3)
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* row constructors, e.g. where (a,b) = any (select a,b from t)
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* ? used in parameterized queries
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# DDL
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* schemas
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* create, drop + drop restrict
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* tables
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* create table
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* constraints: named, null, unique, primary key, foreign key (matches, on update/delete)
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* identity (the weird ansi version), defaults
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* defaults
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* alter table
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* defaults, null, set data type, drop column, constraints
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* drop table + restrict
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* create, drop view
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* create, alter, drop domain
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* defaults, constraints
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* create, drop assertion
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* create, alter, drop sequence
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# Non-query DML
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* delete
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* delete from
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* as alias
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* where
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* truncate
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* with identity options
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* insert
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* values, general queries, defaults
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* update
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* including row updates
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# Access Control
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* grant privileges
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* all, grant option, table, domain, type, sequence, role, etc.
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* revoke
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* create role, drop role
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# Transaction management
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* begin, commit, rollback
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* savepoints
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