查询条件方法
最后更新于：2022-04-02 02:47:20
[TOC]
> [xorm.io参考](https://gobook.io/read/gitea.com/xorm/manual-en-US/)
## 查询条件方法
### Alias(string)
```
engine.Alias("o").Where("o.name = ?", name).Get(&order)
```
### Where()
```
engine.Where("a = ? AND b = ?", 1, 2).Find(&beans)
engine.Where(builder.Eq{"a":1, "b": 2}).Find(&beans)
engine.Where(builder.Eq{"a":1}.Or(builder.Eq{"b": 2})).Find(&beans)
```
### where 可配合其他函数
```
config := new(IM_CONFIG)
config.CFG_TYPE = "system"
_, e := engine.Where(builder.In("CFG_DATA", []string{"3000", "5000"})).Get(config)
//or
engine.In("CFG_DATA", []string{"3000", "5000"}).Get(config)
//or 字段使用实例化后的值
engine.In(config.CFG_DATA, []string{"3000", "5000"}).Get(config)
```
### And()
```
engine.Where("user_id=?", 1).And("user_login=?", "admin").Get(&sysapp)
```
### Asc() 与Desc()
```
engine.Asc("id").Desc("time").Find(&orders)
```
### In()
```
// select from table where column in (1,2,3)
engine.In("app_index", 4, 5).Find(sysapp)
// select from table where column in (1,2,3)
engine.In("column", []int{1, 2, 3}).Find()
//子查询- select from table where column in (select column from table2 where a = 1)
engine.In("column", builder.Select("column").From("table2").Where(builder.Eq{"a":1})).Find()
```
### Limit()
限制获取的数目，第一个参数为条数，第二个参数表示开始位置，如果不传则为0
### OrderBy()
### Cols() 更新或查询特定字段
```
engine.Cols("age", "name").Get(&usr)
// SELECT age, name FROM user limit 1
engine.Cols("age", "name").Find(&users)
// SELECT age, name FROM user
engine.Cols("age", "name").Update(&user)
// UPDATE user SET age=? AND name=?
//映射到 非struct
cfgId :=make([]string,0)
err = Engine.Table(new(SYS_CONFIG)).Cols("CFG_ID").Find(&cfgId)
//获取多个字段的 非struct
cfgId :=make([][]string,0)
err = Engine.Table(new(SYS_CONFIG)).Cols("CFG_ID","CFG_TYPE").Find(&cfgId)
```
## Get() 查询单条
```
根据条件
user := new(User)
has, err := engine.Where("name=?", "xlw").Get(user)
user := &User{Name:"xlw"}
has, err := engine.Get(user)
```
//查询单个字段
```
var ints int64
err := engine.Table("user").Cols("id").Get(&ints)
```
## Find() 查询多条
```
everyone := make([]Userinfo, 0)
err := engine.Find(&everyone)
pEveryOne := make([]*Userinfo, 0)
err := engine.Find(&pEveryOne)
```
//查询单个字段
```
var ints []int64
err := engine.Table("user").Cols("id").Find(&ints)
```
## SQL() 复杂查询时,把sql 语句映射到结构体
```
engine.SQL("select * from table").Find(&beans)
```
## Query()
```
sql := "select * from userinfo"
results, err := engine.Query(sql) //results为 []map[string][]byte
```
## Exec() 执行Insert， Update， Delete 等操作
```
sql = "update `userinfo` set username=? where id=?"
res, err := engine.Exec(sql, "xiaolun", 1)
```
## AllCols()
查询或更新所有字段，一般与Update配合使用，因为默认Update只更新非0，非""，非bool的字段。
```
engine.AllCols().Id(1).Update(&user)
```
## JOIN
```
Join("LEFT","hs_role_member", "hs_role.ROLE_ID=hs_role_member.ROLE_ID")
```
';