MyBatis - Plus条件构造器

说明

• 以下出现的第一个参数 boolean condition 表示该条件是否加入最后生成的sql中
• 以下代码块的多个方法均为从上往下补全个别boolean类型的为入参，默认为true
• 以下出现的泛型This均使用Wrapper的实例
• 以下方法出现的R为泛型，在普通的warapper中是String,在LambdaWrapper的函数（例：Entity::getId,Entity为实体类,getId为字段id的getMethod）
• 以下方法入参中的R column均表示数据库字段,当R为String时则为数据库字段名(字段名是数据库关键字的自己用转义符包裹!)!而不是实体类数据字段名!!!
• 以下举例均为使用普通wrapper,入参为Map和List的均以json形式表现!
• 使用中如果入参的Map或者List为空,则不会加入最后生成的sql中!!!

AbstractWrapper

说明

• QueryWrapper(LambdaQueryWrapper) 和 UpdateWrapper(LambdaUpdateWrapper) 的父类
  用于生成 sql 的 where 条件, entity 属性也用于生成 sql 的 where 条件

allEq

allEq(Map<R, V> params)
allEq(Map<R, V> params, boolean null2IsNull)
allEq(boolean condition, Map<R, V> params, boolean null2IsNull)

• 全部eq(或个别isNull)
• 个别参数说明
  params : key为数据库字段名,value为字段值
  null2IsNull: 为true则在map的value为null时调用 isNull 方法,为false时则忽略value为null的
• 例： allEq({id:1,name:“老王”,age:null})—>id = 1 and name = ‘老王’ and age is null
• 例：allEq({id:1,name:“老王”,age:null}, false)—>id = 1 and name = ‘老王’

allEq(BiPredicate<R, V> filter, Map<R, V> params)
allEq(BiPredicate<R, V> filter, Map<R, V> params, boolean null2IsNull)
allEq(boolean condition, BiPredicate<R, V> filter, Map<R, V> params, boolean null2IsNull) 

个别参数说明:

filter : 过滤函数,是否允许字段传入比对条件中
params 与 null2IsNull : 同上

• 例：allEq((k,v) -> k.indexOf(“a”) > 0, {id:1,name:“老王”,age:null})—>name = ‘老王’ and age is null
• 例： allEq((k,v) -> k.indexOf(“a”) > 0, {id:1,name:“老王”,age:null}, false)—>name = ‘老王’

ep

eq(R column, Object val)
eq(boolean condition, R column, Object val)

• 等于
• 例: eq(“name”, “老王”)—>name = ‘老王’

ne

ne(R column, Object val)
ne(boolean condition, R column, Object val)

• 不等于 <>
• 例: ne(“name”, “老王”)—>name <> ‘老王’

gt

gt(R column, Object val)
gt(boolean condition, R column, Object val)

• 大于>
• 例: gt(“age”, 18)—>age > 18

ge

ge(R column, Object val)
ge(boolean condition, R column, Object val)

• 大于等于>=
• 例: ge(“age”, 18)—>age >= 18

it

lt(R column, Object val)
lt(boolean condition, R column, Object val)

• 小于<
• 例: lt(“age”, 18)—>age < 18

le

le(R column, Object val)
le(boolean condition, R column, Object val)

• 小于等于 <=
• 例：le(“age”, 18)—>age <= 18

between

between(R column, Object val1, Object val2)
between(boolean condition, R column, Object val1, Object val2)

• between 值1 and 值2
• 例: between(“age”, 18, 30)—>age between 18 and 30

notBetween

notBetween(R column, Object val1, Object val2)
notBetween(boolean condition, R column, Object val1, Object val2)

• not between 值1 and 值2
• 例: notBetween(“age”, 18, 30)—>age not between 18 and 30

like

like(R column, Object val)
like(boolean condition, R column, Object val)

• LIKE’%值%’
• 例: like(“name”, “王”)—>name like ‘%王%’

notLike

notLike(R column, Object val)
notLike(boolean condition, R column, Object val)

• NOT LIKE ‘%值%’
• 例: notLike(“name”, “王”)—>name not like ‘%王%’

likeLeft

likeLeft(R column, Object val)
likeLeft(boolean condition, R column, Object val)

• LIKE ‘%值’
• 例: likeLeft(“name”, “王”)—>name like ‘%王’

likeRight

likeRight(R column, Object val)
likeRight(boolean condition, R column, Object val)

• LIKE '值%’
• 例: likeRight(“name”, “王”)—>name like ‘王%’

isNull

isNull(R column)
isNull(boolean condition, R column)

• 字段 is null
• 例: isNull(“name”)—>name is null

isNotNull

isNotNull(R column)
isNotNull(boolean condition, R column)

• 字段 IS NULL
• 例: isNotNull(“name”)—>name is not null

in

in(R column, Collection<?> value)
in(boolean condition, R column, Collection<?> value)

• 字段 IN (value.get(0), value.get(1), …)
• 例: in(“age”,{1,2,3})—>age in (1,2,3)

in(R column, Object... values)
in(boolean condition, R column, Object... values)

• 字段 IN (v0, v1, …)
• 例: in(“age”, 1, 2, 3)—>age in (1,2,3)

notIn

notIn(R column, Collection<?> value)
notIn(boolean condition, R column, Collection<?> value)

• 字段 IN (value.get(0), value.get(1), …)
• 例: notIn(“age”,{1,2,3})—>age not in (1,2,3)

notIn(R column, Object... values)
notIn(boolean condition, R column, Object... values)

• 字段 NOT IN (v0, v1, …)
• 例: notIn(“age”, 1, 2, 3)—>age not in (1,2,3)

inSql

inSql(R column, String inValue)
inSql(boolean condition, R column, String inValue)

• 字段 IN ( sql语句 )
• 例: inSql(“age”, “1,2,3,4,5,6”)—>age in (1,2,3,4,5,6)
• 例: inSql(“id”, “select id from table where id < 3”)—>id in (select id from table where id < 3)

notInSql

notInSql(R column, String inValue)
notInSql(boolean condition, R column, String inValue)

• 字段 NOT IN ( sql语句 )
• 例: notInSql(“age”, “1,2,3,4,5,6”)—>age not in (1,2,3,4,5,6)
• 例: notInSql(“id”, “select id from table where id < 3”)—>age not in (select id from table where id < 3)

gruupBy

groupBy(R... columns)
groupBy(boolean condition, R... columns)

• 分组：GROUP BY 字段, …
• 例: groupBy(“id”, “name”)—>group by id,name

orderByAsc

orderByAsc(R... columns)
orderByAsc(boolean condition, R... columns)

• 排序：ORDER BY 字段, … ASC
• 例: orderByAsc(“id”, “name”)—>order by id ASC,name ASC

orderByDesc

orderByDesc(R... columns)
orderByDesc(boolean condition, R... columns)

• 排序：ORDER BY 字段, … DESC
• 例: orderByDesc(“id”, “name”)—>order by id DESC,name DESC

orderBy

orderBy(boolean condition, boolean isAsc, R... columns)

• 排序：ORDER BY 字段, …
• 例: orderBy(true, true, “id”, “name”)—>order by id ASC,name ASC

having

having(String sqlHaving, Object... params)
having(boolean condition, String sqlHaving, Object... params)

• HAVING ( sql语句 )
• 例: having(“sum(age) > 10”)—>having sum(age) > 10
• 例: having(“sum(age) > {0}”, 11)—>having sum(age) > 11

or

or()
or(boolean condition)

• 拼接 OR

注意事项:

主动调用or表示紧接着下一个方法不是用and连接!(不调用or则默认为使用and连接)

• 例: eq(“id”,1).or().eq(“name”,“老王”)—>id = 1 or name = ‘老王’

or(Function<This, This> func)
or(boolean condition, Function<This, This> func)

• OR 嵌套
• 例: or(i -> i.eq(“name”, “李白”).ne(“status”, “活着”))—>or (name = ‘李白’ and status <> ‘活着’)

and

and(Function<This, This> func)
and(boolean condition, Function<This, This> func)

• AND 嵌套
• 例: and(i -> i.eq(“name”, “李白”).ne(“status”, “活着”))—>and (name = ‘李白’ and status <> ‘活着’)

apply

apply(String sqlHaving, Object... params)
apply(boolean condition, String sqlHaving, Object... params)

• 拼接 sql

注意事项:

该方法可用于数据库函数 动态入参的params对应前面sqlHaving内部的{index}部分.这样是不会有sql注入风险的,反之会有!

• 例: apply(“id = 1”)—>having sum(age) > 10
• 例: apply(“date_format(dateColumn,’%Y-%m-%d’) = ‘2008-08-08’”)—>date_format(dateColumn,’%Y-%m-%d’) = ‘2008-08-08’")
• 例: apply(“date_format(dateColumn,’%Y-%m-%d’) = {0}”, “2008-08-08”)—>date_format(dateColumn,’%Y-%m-%d’) = ‘2008-08-08’")

last

last(String lastSql)
last(boolean condition, String lastSql)

• 无视优化规则直接拼接到 sql 的最后

注意事项:

只能调用一次,多次调用以最后一次为准 有sql注入的风险,请谨慎使用

• 例: last(“limit 1”)

exists

exists(String existsSql)
exists(boolean condition, String existsSql)

• 拼接 EXISTS ( sql语句 )
• 例: exists(“select id from table where age = 1”)—>exists (select id from table where age = 1)

notExists

notExists(String existsSql)
notExists(boolean condition, String existsSql)

• 拼接 NOT EXISTS ( sql语句 )
• 例: notExists(“select id from table where age = 1”)—>not exists (select id from table where age = 1)

nested

nested(Function<This, This> func)
nested(boolean condition, Function<This, This> func)

• 正常嵌套 不带 AND 或者 OR
• 例: nested(i -> i.eq(“name”, “李白”).ne(“status”, “活着”))—>(name = ‘李白’ and status <> ‘活着’)

QueryWrapper

说明:

继承自 AbstractWrapper ,自身的内部属性 entity 也用于生成 where 条件
及 LambdaQueryWrapper, 可以通过 new QueryWrapper().lambda() 方法获取

select

select(String... sqlSelect)
select(Predicate<TableFieldInfo> predicate)
select(Class<T> entityClass, Predicate<TableFieldInfo> predicate)

• 设置查询字段
• 说明:

以上方分法为两类.
第二类方法为:过滤查询字段(主键除外),入参不包含 class 的调用前需要wrapper内的entity属性有值! 这两类方法重复调用以最后一次为准

• 例: select(“id”, “name”, “age”)
• 例: select(i -> i.getProperty().startsWith(“test”))

set

set(String column, Object val)
set(boolean condition, String column, Object val)

• SQL SET 字段
• 例: set(“name”, “老李头”)
• 例: set(“name”, “”)—>数据库字段值变为空字符串
• 例: set(“name”, null)—>数据库字段值变为null

setSql

setSql(String sql)

• 设置 SET 部分 SQL
• 例: set("name = ‘老李头’)