SQL Expressions

SQL expression builders. All SQL expressions are represented in the form of an abstract syntax tree (AST). Helper methods and functions build out this tree.

column

column(name)

Create an expression AST node that references a column by name. Upon string coercion, the column name will be properly quoted.

literal

literal(value)

Create an expression AST node that references a literal value. Upon string coercion, an appropriate SQL value will be produced. For example, string literals will be properly quoted and JavaScript Date objects that match an extact UTC date will be converted to the SQL Date definitions. The supported primitive types are: boolean, null, number, string, regexp, and Date (maps to SQL Date or Timestamp depending on the value).

sql

sql`...`

A template tag for arbitrary SQL expressions that do not require deep analysis. Creates an expression AST node with only a partially structured form consisting of unstructured text and interpolated values. Interpolated values may be strings, other SQL expressions (such as column references or operators), or Param values.

The snippet below creates a dynamic expression that adds a Param value to a column. Contained column references can be extracted using the collectColumns method. Contained Param values can be extracted using the collectParams method.

const param = Param.value(5);
sql`${column("foo")} + ${param}`

SQL expressions may be nested, in which case all nested column dependencies and parameter updates are still extractable via the collection visitors.