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256 lines (203 loc) · 6.98 KB
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'use strict';
const has = require('has');
const escapeMap = {
'\0': '\\0',
'\'': '\\\'',
'"': '\\"',
'\b': '\\b',
'\n': '\\n',
'\r': '\\r',
'\t': '\\t',
'\x1a': '\\Z', // EOF
'\\': '\\\\'
};
function escape(str) {
const res = [];
let char;
for (let i = 0, l = str.length; i < l; ++i) {
char = str[i];
const escaped = escapeMap[char];
if (escaped) char = escaped;
res.push(char);
}
return res.join('');
}
function literalToSQL(literal) {
const { type } = literal;
let { value } = literal;
if (type === 'number') {
/* nothing */
} else if (type === 'string') value = '\'' + escape(value) + '\'';
else if (type === 'bool') value = value ? 'TRUE' : 'FALSE';
else if (type === 'null') value = 'NULL';
else if (type === 'star') value = '*';
else if (['time', 'date', 'timestamp'].includes(type)) value = `${type.toUpperCase()} '${value}'`;
return !literal.parentheses ? value : '(' + value + ')';
}
let exprToSQLConvertFn = {};
function exprToSQL(expr) {
return exprToSQLConvertFn[expr.type] ? exprToSQLConvertFn[expr.type](expr) : literalToSQL(expr);
}
function aggrToSQL(expr) {
/** @type {Object} */
const args = expr.args;
let str = exprToSQL(args.expr);
const fnName = expr.name;
if (fnName === 'COUNT') {
if (has(args, 'distinct') && args.distinct !== null) str = 'DISTINCT ' + str;
}
return fnName + '(' + str + ')';
}
function binaryToSQL(expr) {
let operator = expr.operator;
let rstr = exprToSQL(expr.right);
if (Array.isArray(rstr)) {
if (operator === '=') operator = 'IN';
if (operator === '!=') operator = 'NOT IN';
if (operator === 'BETWEEN') rstr = rstr[0] + ' AND ' + rstr[1];
else rstr = '(' + rstr.join(', ') + ')';
}
const str = exprToSQL(expr.left) + ' ' + operator + ' ' + rstr;
return !expr.parentheses ? str : '(' + str + ')';
}
function caseToSQL(expr) {
const res = ['CASE'];
const conditions = expr.args;
if (expr.expr) res.push(exprToSQL(expr.expr));
for (let i = 0, l = conditions.length; i < l; ++i) {
res.push(conditions[i].type.toUpperCase()); // when/else
if (conditions[i].cond) {
res.push(exprToSQL(conditions[i].cond));
res.push('THEN');
}
res.push(exprToSQL(conditions[i].result));
}
res.push('END');
return res.join(' ');
}
function castToSQL(expr) {
let str = 'CAST(';
str += exprToSQL(expr.expr) + ' AS ';
str += expr.target.dataType + (expr.target.length ? '(' + expr.target.length + ')' : '');
str += ')';
return str;
}
function columnRefToSQL(expr) {
let str = expr.column !== '*' ? '"' + expr.column + '"' : '*';
if (has(expr, 'table') && expr.table !== null) str = '"' + expr.table + '".' + str;
return !expr.parentheses ? str : '(' + str + ')';
}
function getExprListSQL(exprList) {
return exprList.map(exprToSQL);
}
function funcToSQL(expr) {
const str = expr.name + '(' + exprToSQL(expr.args).join(', ') + ')';
return !expr.parentheses ? str : '(' + str + ')';
}
/**
* Stringify column expressions
*
* @param {Array} columns
* @return {string}
*/
function columnsToSQL(columns) {
return columns
.map((column) => {
let str = exprToSQL(column.expr);
if (column.as !== null) {
str += ' AS ';
if (column.as.match(/^[a-z_][0-9a-z_]*$/i)) str += '"' + column.as + '"';
else str += '\'' + column.as + '\'';
}
return str;
})
.join(', ');
}
/**
* @param {Array} tables
* @return {string}
*/
function tablesToSQL(tables) {
const baseTable = tables[0];
const clauses = [];
let str = baseTable.table ? '"' + baseTable.table + '"' : exprToSQL(baseTable.expr);
if (baseTable.db && baseTable.db !== null) str = baseTable.db + '.' + str;
if (baseTable.as !== null) str += ' AS "' + baseTable.as + '"';
clauses.push(str);
for (let i = 1; i < tables.length; i++) {
const joinExpr = tables[i];
str = (joinExpr.join && joinExpr.join !== null) ? ' ' + joinExpr.join + ' ' : str = ', ';
if (joinExpr.table) {
if (joinExpr.db !== null) str += (joinExpr.db + '.');
str += '"' + joinExpr.table + '"';
} else {
str += exprToSQL(joinExpr.expr);
}
if (joinExpr.as !== null) str += ' AS "' + joinExpr.as + '"';
if (has(joinExpr, 'on') && joinExpr.on !== null) str += ' ON ' + exprToSQL(joinExpr.on);
clauses.push(str);
}
return clauses.join('');
}
/**
* @param {Object} stmt
* @param {?Array} stmt.options
* @param {?string} stmt.distinct
* @param {?Array|string} stmt.columns
* @param {?Array} stmt.from
* @param {?Object} stmt.where
* @param {?Array} stmt.groupby
* @param {?Object} stmt.having
* @param {?Array} stmt.orderby
* @param {?Array} stmt.limit
* @return {string}
*/
function selectToSQL(stmt) {
const clauses = ['SELECT'];
if (has(stmt, 'options') && Array.isArray(stmt.options)) clauses.push(stmt.options.join(' '));
if (has(stmt, 'distinct') && stmt.distinct !== null) clauses.push(stmt.distinct);
if (stmt.columns !== '*') clauses.push(columnsToSQL(stmt.columns));
else clauses.push('*');
// FROM + joins
if (Array.isArray(stmt.from)) clauses.push('FROM', tablesToSQL(stmt.from));
if (has(stmt, 'where') && stmt.where !== null) clauses.push('WHERE ' + exprToSQL(stmt.where));
if (Array.isArray(stmt.groupby)) clauses.push('GROUP BY', getExprListSQL(stmt.groupby).join(', '));
if (has(stmt, 'having') && stmt.having !== null) clauses.push('HAVING ' + exprToSQL(stmt.having));
if (Array.isArray(stmt.orderby)) {
const orderExpressions = stmt.orderby.map(expr => exprToSQL(expr.expr) + ' ' + expr.type);
clauses.push('ORDER BY', orderExpressions.join(', '));
}
if (Array.isArray(stmt.limit)) clauses.push('LIMIT', stmt.limit.map(exprToSQL));
return clauses.join(' ');
}
function unaryToSQL(expr) {
const str = expr.operator + ' ' + exprToSQL(expr.expr);
return !expr.parentheses ? str : '(' + str + ')';
}
function unionToSQL(stmt) {
const res = [selectToSQL(stmt)];
while (stmt._next) {
res.push('UNION', selectToSQL(stmt._next));
stmt = stmt._next;
}
return res.join(' ');
}
exprToSQLConvertFn = {
aggr_func: aggrToSQL,
binary_expr: binaryToSQL,
case: caseToSQL,
cast: castToSQL,
column_ref: columnRefToSQL,
expr_list: expr => getExprListSQL(expr.value),
function: funcToSQL,
select: (expr) => {
let str = selectToSQL(expr);
if (expr.parentheses) str = '(' + str + ')';
return str;
},
unary_expr: unaryToSQL
};
module.exports = function toSQL(ast) {
if (ast.type !== 'select') throw new Error('Only SELECT statements supported at the moment');
return unionToSQL(ast);
};