diff --git a/lib/api.js b/lib/api.js
index 5b0e880..407813a 100644
--- a/lib/api.js
+++ b/lib/api.js
@@ -39,7 +39,8 @@ class Api {
       throw new SqlErr('Query Error: empty table')
     }
     name = fixtable(name)
-    return new Method(this.pool, this.slave, this.db, name)
+
+    return new Method(this.pool, this.slave, this.db, name, this.debug)
   }
 
   /**
@@ -59,6 +60,10 @@ class Api {
     return this.connect().then(conn => {
       let defer = Promise.defer()
 
+      if (this.debug) {
+        console.log('[debug]', sql)
+      }
+
       conn.query(sql, (err, result) => {
         conn.release()
         if (err) {
@@ -74,52 +79,22 @@ class Api {
     if (!this.db && db) {
       return Promise.reject('No database selected.')
     }
-    this.db = db || this.db
     let defer = Promise.defer()
 
-    this.connect().then(conn => {
-      conn.query(`DROP DATABASE IF EXISTS ${db || this.db}`, err => {
-        conn.release()
-        if (err) {
-          return defer.reject(new SqlErr(`Drop database ${err}`))
-        }
-        defer.resolve(true)
-      })
-    })
-    return defer.promise
+    return this.query(`DROP DATABASE IF EXISTS ${db || this.db}`)
   }
 
   dbList() {
-    return this.connect().then(conn => {
-      let defer = Promise.defer()
-
-      conn.query('SHOW DATABASES', (err, row) => {
-        conn.release()
-        if (err) {
-          return defer.reject(new SqlErr('Show databases ' + err))
-        }
-        defer.resolve(row.map(it => it.Database))
-      })
-
-      return defer.promise
-    })
+    return this.query('SHOW DATABASES').then(list =>
+      list.map(it => it.Database)
+    )
   }
 
   //返回数据表
   tableList() {
-    return this.connect().then(conn => {
-      let defer = Promise.defer()
-
-      conn.query('SHOW TABLES', (err, row) => {
-        conn.release()
-        if (err) {
-          return defer.reject(new SqlErr('Show tables ' + err))
-        }
-        defer.resolve(row.map(it => it[Object.keys(it)[0]]))
-      })
-
-      return defer.promise
-    })
+    return this.query('SHOW TABLES').then(list =>
+      list.map(it => it[Object.keys(it)[0]])
+    )
   }
 
   // 创建新的数据库
@@ -127,21 +102,9 @@ class Api {
     if (!name) {
       return Promise.reject('Empty database name.')
     }
-
     let sql = `CREATE DATABASE \`${name}\` DEFAULT CHARACTER SET = \`${charset}\``
-    return this.connect().then(conn => {
-      let defer = Promise.defer()
 
-      conn.query(sql, (err, result) => {
-        conn.release()
-        if (err) {
-          return defer.reject(new SqlErr('Create database ' + err))
-        }
-        defer.resolve(true)
-      })
-
-      return defer.promise
-    })
+    return this.query(sql)
   }
 
   // 创建新的表,
@@ -160,19 +123,7 @@ class Api {
 
     sql += ` ENGINE=${engine} DEFAULT CHARSET=${charset}`
 
-    return this.connect().then(conn => {
-      let defer = Promise.defer()
-
-      conn.query(sql, (err, result) => {
-        conn.release()
-        if (err) {
-          return defer.reject(new SqlErr('Create table ' + err, sql))
-        }
-        defer.resolve(true)
-      })
-
-      return defer.promise
-    })
+    return this.query(sql)
   }
 }
 
diff --git a/lib/method.js b/lib/method.js
index 5807a09..a815eaf 100644
--- a/lib/method.js
+++ b/lib/method.js
@@ -7,33 +7,42 @@
 const { SqlErr, parser, escape, fixtable } = require('./utils')
 
 class Method {
-  constructor(pool, slave, db, table) {
+  constructor(pool, slave, db, table, debug = false) {
     this.pool = pool
     this.slave = slave
     this.db = db
     this.cache = { table }
+    this.debug = debug
   }
 
-  connect() {
+  _connect() {
     let defer = Promise.defer()
     this.pool.getConnection(this.slave, (err, conn) => {
       if (err) {
         return defer.reject(new SqlErr(`MySQL connect ${err}`))
       }
-      if (this.db) {
-        conn.query('USE ' + this.db, err => {
-          if (err) {
-            return defer.reject(new SqlErr('Use DB ' + err))
-          }
-          defer.resolve(conn)
-        })
-      } else {
-        defer.resolve(conn)
-      }
+      defer.resolve(conn)
     })
     return defer.promise
   }
 
+  _query(sql) {
+    return this._connect().then(conn => {
+      let defer = Promise.defer()
+      if (this.debug) {
+        console.log('[debug]', sql)
+      }
+      conn.query(sql, (err, result) => {
+        conn.release()
+        if (err) {
+          return defer.reject(new SqlErr(`MySQL ${err}`, sql))
+        }
+        defer.resolve(result)
+      })
+      return defer.promise
+    })
+  }
+
   leftJoin(tables) {
     this.cache.leftJoin = tables
     return this
@@ -97,7 +106,7 @@ class Method {
    * [withFields 选取指定的字段]
    * @param {string[]} fields [以数组形式传入]
    */
-  withFields(fields) {
+  withFields(...fields) {
     this.cache.fields = fields
     return this
   }
@@ -166,18 +175,7 @@ class Method {
       sql += parser.limit(limit)
     }
 
-    return this.connect().then(conn => {
-      let defer = Promise.defer()
-
-      conn.query(sql, (err, result) => {
-        conn.release()
-        if (err) {
-          return defer.reject(new SqlErr(`Find ${err}`, sql))
-        }
-        defer.resolve(result)
-      })
-      return defer.promise
-    })
+    return this._query(sql)
   }
 
   /**
@@ -219,20 +217,7 @@ class Method {
     }
     sql += `(${keys.join(',')}) VALUES (${vals.join(',')})`
 
-    return this.connect().then(conn => {
-      const defer = Promise.defer()
-
-      conn.query(sql, (err, result) => {
-        conn.release()
-        if (err) {
-          return defer.reject(new SqlErr(`Insert ${err}`, sql))
-        }
-
-        defer.resolve(result.insertId)
-      })
-
-      return defer.promise
-    })
+    return this._query(sql)
   }
 
   /**
@@ -259,20 +244,7 @@ class Method {
     sql += fields.join(',')
     sql += parser.filter(filter)
 
-    return this.connect().then(conn => {
-      const defer = Promise.defer()
-
-      conn.query(sql, (err, result) => {
-        conn.release()
-        if (err) {
-          return defer.reject(new SqlErr(`Update ${err}`, sql))
-        }
-
-        defer.resolve(result.affectedRows)
-      })
-
-      return defer.promise
-    })
+    return this._query(sql)
   }
 
   /**
@@ -284,86 +256,34 @@ class Method {
     let sql = `DELETE FROM ${table} `
     sql += parser.filter(filter)
 
-    return this.connect().then(conn => {
-      const defer = Promise.defer()
-
-      conn.query(sql, (err, result) => {
-        conn.release()
-        if (err) {
-          return defer.reject(new SqlErr(`Remove ${err}`, sql))
-        }
-
-        defer.resolve(result.affectedRows)
-      })
-
-      return defer.promise
-    })
+    return this._query(sql)
   }
 
   drop() {
     let sql = `DROP TABLE IF EXISTS ${this.cache.table} `
 
-    return this.connect().then(conn => {
-      const defer = Promise.defer()
-
-      conn.query(sql, (err, result) => {
-        conn.release()
-        if (err) {
-          return defer.reject(new SqlErr(`Drop table ${err}`, sql))
-        }
-
-        defer.resolve(true)
-      })
-
-      return defer.promise
-    })
+    return this._query(sql)
   }
 
   // 重命名表
   renameTo(name) {
-    return this.connect().then(conn => {
-      const defer = Promise.defer()
-
-      let sql = `RENAME TABLE ${this.cache.table} TO ${fixtable(name)}`
-      conn.query(sql, (err, result) => {
-        conn.release()
-        if (err) {
-          return defer.reject(new SqlErr(`List index ${err}`, sql))
-        }
-
-        defer.resolve(true)
-      })
-
-      return defer.promise
-    })
+    let sql = `RENAME TABLE ${this.cache.table} TO ${fixtable(name)}`
+    return this._query(sql)
   }
 
   // 返回索引列表
   indexList() {
-    return this.connect().then(conn => {
-      const defer = Promise.defer()
+    let sql = `SHOW INDEX FROM ${this.cache.table}`
 
-      let sql = `SHOW INDEX FROM ${this.cache.table}`
-      conn.query(sql, (err, result) => {
-        conn.release()
-        if (err) {
-          return defer.reject(new SqlErr(`List index ${err}`, sql))
-        }
-        let list = result.map(it => {
-          return {
-            name: it.Key_name,
-            column: it.Column_name,
-            unique: !it.Non_unique,
-            cardinality: it.Cardinality,
-            collation: it.Collation
-          }
-        })
-
-        defer.resolve(list)
-      })
-
-      return defer.promise
-    })
+    return this._query(sql).then(list =>
+      list.map(it => ({
+        name: it.Key_name,
+        column: it.Column_name,
+        unique: !it.Non_unique,
+        cardinality: it.Cardinality,
+        collation: it.Collation
+      }))
+    )
   }
 
   // 删除指定索引
@@ -371,21 +291,9 @@ class Method {
     if (!name) {
       return Promise.reject('Empty index name')
     }
-    return this.connect().then(conn => {
-      const defer = Promise.defer()
 
-      let sql = `ALTER TABLE ${this.cache.table} DROP INDEX \`${name}\``
-      conn.query(sql, (err, result) => {
-        conn.release()
-        if (err) {
-          return defer.reject(new SqlErr(`Drop index ${err}`, sql))
-        }
-
-        defer.resolve(true)
-      })
-
-      return defer.promise
-    })
+    let sql = `ALTER TABLE ${this.cache.table} DROP INDEX \`${name}\``
+    return this._query(sql)
   }
 
   // 删除指定索引
@@ -402,24 +310,11 @@ class Method {
       unique = 'UNIQUE'
     }
 
-    return this.connect().then(conn => {
-      const defer = Promise.defer()
+    let sql = `ALTER TABLE ${
+      this.cache.table
+    } ADD ${unique} INDEX \`${name}\` (${opt.field})`
 
-      let sql = `ALTER TABLE ${
-        this.cache.table
-      } ADD ${unique} INDEX \`${name}\` (${opt.field})`
-
-      conn.query(sql, (err, result) => {
-        conn.release()
-        if (err) {
-          return defer.reject(new SqlErr(`Drop index ${err}`, sql))
-        }
-
-        defer.resolve(true)
-      })
-
-      return defer.promise
-    })
+    return this._query(sql)
   }
 }
 
diff --git a/lib/utils.js b/lib/utils.js
index e2c079f..868502a 100644
--- a/lib/utils.js
+++ b/lib/utils.js
@@ -102,7 +102,7 @@ function parse$opt(opt) {
         if (tmp.hasOwnProperty('$gt') || tmp.hasOwnProperty('$gte')) {
           let oc = tmp.hasOwnProperty('$gt') ? '>' : '>='
           let val = tmp.hasOwnProperty('$gt') ? tmp.$gt : tmp.$gte
-          sql += ` ${k} >${oc} ${escape(val)} `
+          sql += ` ${k} ${oc} ${escape(val)} `
           break
         }
 
diff --git a/package.json b/package.json
index 1dc1dba..ac66446 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "mysqli",
-  "version": "3.0.12",
+  "version": "3.1.0",
   "description": "MySQL tool",
   "main": "index.js",
   "dependencies": {