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JavaScript
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2025-09-04 10:49:10 +08:00
class QueryBuilder {
constructor() {
this.conditions = {};
this.limit = null;
this.offset = null;
this.groupBy = null;
}
where(condition, ...params) {
this.conditions[condition] = params;
return this;
}
setLimit(limit) {
this.limit = limit;
return this;
}
setOffset(offset) {
this.offset = offset;
return this;
}
setGroupBy(groupBy) {
this.groupBy = groupBy;
return this;
}
sqdata(sql, params) {
return new Promise((resolve, reject) => {
global.sqlReq.query(sql, params, (err, result) => {
if (err) {
reject(err);
}
resolve(result);
});
});
}
getParams() {
return Object.values(this.conditions).flat();
}
buildConditions() {
return Object.keys(this.conditions).map(condition => `${condition}`).join(' AND ');
}
}
class SelectBuilder extends QueryBuilder {
constructor() {
super();
this.selectFields = [];
this.tables = [];
this.orderByField = '';
this.orderByDirection = 'ASC';
this.subQueries = []; // 用于存储子查询
this.unions = []; // 存储UNION查询
}
// 添加UNION查询
union(queryBuilder, type = 'UNION') {
this.unions.push({queryBuilder, type});
return this;
}
// 添加UNION ALL查询
unionAll(queryBuilder) {
this.union(queryBuilder, 'UNION ALL');
return this;
}
// 构建主查询部分不含ORDER BY/LIMIT/OFFSET
buildMainQuery() {
const subQuerySQL = this.subQueries.map(({alias, subQuery}) => `(${subQuery}) AS ${alias}`);
const selectClause = this.selectFields.concat(subQuerySQL).join(', ');
let sql = `SELECT ${selectClause}
FROM ${this.tables.join(' ')}`;
const conditionClauses = this.buildConditions();
if (conditionClauses) {
sql += ` WHERE ${conditionClauses}`;
}
if (this.groupBy) {
sql += ` GROUP BY ${this.groupBy}`;
}
const params = this.getParams();
return {sql, params};
}
// 供UNION查询调用的构建方法
buildForUnion() {
return this.buildMainQuery();
}
select(fields) {
this.selectFields = fields.split(',').map(field => field.trim());
return this;
}
// 添加子查询
addSubQuery(alias, subQuery) {
this.subQueries.push({alias, subQuery});
return this;
}
whereLike(fields, keyword) {
const likeConditions = fields.map(field => `${field} LIKE ?`).join(' OR ');
this.conditions[likeConditions] = fields.map(() => `%${keyword}%`);
return this;
}
from(table) {
this.tables.push(table);
return this;
}
leftJoin(table, condition) {
this.tables.push(`LEFT JOIN ${table} ON ${condition}`);
return this;
}
orderBy(field, direction = 'ASC') {
this.orderByField = field;
this.orderByDirection = direction.toUpperCase();
return this;
}
paginate(page, pageSize) {
if (page <= 0 || pageSize <= 0) {
throw new Error('分页参数必须大于0');
}
this.limit = pageSize;
this.offset = (page - 1) * pageSize;
return this;
}
async chidBuild() {
let sql = `SELECT ${this.selectFields.join(', ')}
FROM ${this.tables.join(' ')}`;
let conditionClauses = this.buildConditions();
if (conditionClauses) {
sql += ` WHERE ${conditionClauses}`;
}
if (this.orderByField) {
sql += ` ORDER BY ${this.orderByField} ${this.orderByDirection}`;
}
if (this.limit !== null) {
sql += ` LIMIT ${this.limit}`;
}
if (this.offset !== null) {
sql += ` OFFSET ${this.offset}`;
}
return sql;
}
async build() {
const main = this.buildMainQuery();
let fullSql = `(${main.sql})`;
const allParams = [...main.params];
// 处理UNION部分
for (const union of this.unions) {
const unionBuilder = union.queryBuilder;
if (!(unionBuilder instanceof SelectBuilder)) {
throw new Error('UNION query must be a SelectBuilder instance');
}
const unionResult = unionBuilder.buildForUnion();
fullSql += ` ${union.type} (${unionResult.sql})`;
allParams.push(...unionResult.params);
}
// 添加ORDER BY、LIMIT、OFFSET
if (this.orderByField) {
fullSql += ` ORDER BY ${this.orderByField} ${this.orderByDirection}`;
}
if (this.limit !== null) {
fullSql += ` LIMIT ${this.limit}`;
}
if (this.offset !== null) {
fullSql += ` OFFSET ${this.offset}`;
}
console.log(fullSql,allParams);
return await this.sqdata(fullSql, allParams);
}
}
class UpdateBuilder extends QueryBuilder {
constructor() {
super();
this.table = '';
this.updateFields = {};
}
update(table) {
this.table = table;
return this;
}
set(field, value) {
if (value && value.increment && typeof value === 'object' ) {
this.updateFields[field] = {increment: value.increment};
} else {
this.updateFields[field] = value;
}
return this;
}
async build() {
let sql = `UPDATE ${this.table}
SET `;
let updateClauses = Object.keys(this.updateFields).map(field => {
const value = this.updateFields[field];
if (value && value.increment && typeof value === 'object' ) {
return `${field} = ${field} + ?`;
}
return `${field} = ?`;
}).join(', ');
sql += updateClauses;
let conditionClauses = this.buildConditions();
if (conditionClauses) {
sql += ` WHERE ${conditionClauses}`;
}
// 处理参数,确保自增字段也传入增量值
const params = [
...Object.values(this.updateFields).map(value =>
(value && value.increment && typeof value === 'object' ) ? value.increment : value
),
...this.getParams()
];
return await this.sqdata(sql, params);
}
}
class InsertBuilder extends QueryBuilder {
constructor() {
super();
this.table = '';
this.insertValues = [];
this.updateValues = {};
}
insertInto(table) {
this.table = table;
return this;
}
// 仍然保留单条记录的插入
values(values) {
if (Array.isArray(values)) {
this.insertValues = values;
} else {
this.insertValues = [values]; // 将单条记录包装成数组
}
return this;
}
// 新增方法,支持一次插入多条记录
valuesMultiple(records) {
if (!Array.isArray(records) || records.length === 0) {
throw new Error('Values must be a non-empty array');
}
// 确保每一条记录都是对象
records.forEach(record => {
if (typeof record !== 'object') {
throw new Error('Each record must be an object');
}
});
this.insertValues = records;
return this;
}
// 新增 upsert 方法,支持更新或插入
upsert(values, updateFields) {
// values: 要插入的记录
// updateFields: 如果记录存在时,需要更新的字段
if (!Array.isArray(values) || values.length === 0) {
throw new Error('Values must be a non-empty array');
}
// 检查每条记录是否是对象
values.forEach(record => {
if (typeof record !== 'object') {
throw new Error('Each record must be an object');
}
});
this.insertValues = values;
this.updateValues = updateFields || {};
return this;
}
async build() {
if (this.insertValues.length === 0) {
throw new Error("No values to insert");
}
// 获取表单列名,假设所有记录有相同的字段
const columns = Object.keys(this.insertValues[0]);
// 构建 VALUES 子句,支持批量插入
const valuePlaceholders = this.insertValues.map(() =>
`(${columns.map(() => '?').join(', ')})`
).join(', ');
// 展平所有的插入值
const params = this.insertValues.flatMap(record =>
columns.map(column => record[column])
);
// 如果有 updateFields构建 ON DUPLICATE KEY UPDATE 子句
let updateClause = '';
if (Object.keys(this.updateValues).length > 0) {
updateClause = ' ON DUPLICATE KEY UPDATE ' +
Object.keys(this.updateValues).map(field => {
return `${field} = VALUES(${field})`;
}).join(', ');
}
// 生成 SQL 语句
const sql = `INSERT INTO ${this.table} (${columns.join(', ')})
VALUES ${valuePlaceholders} ${updateClause}`;
// 执行查询
return await this.sqdata(sql, params);
}
}
class DeleteBuilder extends QueryBuilder {
constructor() {
super();
this.table = '';
}
deleteFrom(table) {
this.table = table;
return this;
}
async build() {
let sql = `DELETE
FROM ${this.table}`;
let conditionClauses = this.buildConditions();
if (conditionClauses) {
sql += ` WHERE ${conditionClauses}`;
}
return await this.sqdata(sql, this.getParams());
}
}
module.exports = {
SelectBuilder,
UpdateBuilder,
InsertBuilder,
DeleteBuilder,
};