docs: update readme

This commit is contained in:
开源海哥 2023-07-26 17:15:01 +08:00
parent c84ab17433
commit fdaa3f7d19

View File

@ -22,7 +22,7 @@
## QQ 群
群号: 532992631
群号: 850176767
![](./docs/assets/images/qq_group.png)
@ -132,7 +132,7 @@ Page<Account> accounts = mapper.paginate(5, 10, query);
QueryWrapper query = new QueryWrapper();
query.select().from(ACCOUNT);
// SQL:
// SQL:
// SELECT * FROM tb_account
```
也可以通过静态方法简写成如下两种形式,效果完全相同:
@ -143,7 +143,7 @@ QueryWrapper query = QueryWrapper.create()
// 方式2
QueryWrapper query = select().from(ACCOUNT);
// SQL:
// SQL:
// SELECT * FROM tb_account
```
### select columns
@ -154,8 +154,8 @@ QueryWrapper query = new QueryWrapper();
query.select(ACCOUNT.ID, ACCOUNT.USER_NAME)
.from(ACCOUNT);
// SQL:
// SELECT id, user_name
// SQL:
// SELECT id, user_name
// FROM tb_account
```
@ -169,9 +169,9 @@ QueryWrapper query = new QueryWrapper()
.from(ACCOUNT.as("a"), ARTICLE.as("b"))
.where(ACCOUNT.ID.eq(ARTICLE.ACCOUNT_ID));
// SQL:
// SELECT a.id, a.user_name, b.id AS articleId, b.title
// FROM tb_account AS a, tb_article AS b
// SQL:
// SELECT a.id, a.user_name, b.id AS articleId, b.title
// FROM tb_account AS a, tb_article AS b
// WHERE a.id = b.account_id
```
@ -186,10 +186,10 @@ QueryWrapper query = new QueryWrapper()
avg(ACCOUNT.SEX).as("sex_avg")
).from(ACCOUNT);
// SQL:
// SELECT id, user_name,
// MAX(birthday),
// AVG(sex) AS sex_avg
// SQL:
// SELECT id, user_name,
// MAX(birthday),
// AVG(sex) AS sex_avg
// FROM tb_account
```
@ -203,10 +203,10 @@ QueryWrapper queryWrapper = QueryWrapper.create()
.where(ACCOUNT.ID.ge(100))
.and(ACCOUNT.USER_NAME.like("michael"));
// SQL:
// SELECT * FROM tb_account
// WHERE id >= ?
// AND user_name LIKE ?
// SQL:
// SELECT * FROM tb_account
// WHERE id >= ?
// AND user_name LIKE ?
```
### where 动态条件 1
@ -218,9 +218,9 @@ QueryWrapper queryWrapper = QueryWrapper.create()
.where(flag ? ACCOUNT.ID.ge(100) : noCondition())
.and(ACCOUNT.USER_NAME.like("michael"));
// SQL:
// SELECT * FROM tb_account
// WHERE user_name LIKE ?
// SQL:
// SELECT * FROM tb_account
// WHERE user_name LIKE ?
```
### where 动态条件 2
@ -232,9 +232,9 @@ QueryWrapper queryWrapper = QueryWrapper.create()
.where(ACCOUNT.ID.ge(100).when(flag))
.and(ACCOUNT.USER_NAME.like("michael"));
// SQL:
// SELECT * FROM tb_account
// WHERE user_name LIKE ?
// SQL:
// SELECT * FROM tb_account
// WHERE user_name LIKE ?
```
### where 自动忽略 null 值
当遇到条件值为 null 时,会自动忽略该条件,不会拼接到 SQL 中
@ -247,9 +247,9 @@ QueryWrapper queryWrapper = QueryWrapper.create()
.where(ACCOUNT.ID.ge(num))
.and(ACCOUNT.USER_NAME.like(userName));
// SQL:
// SELECT * FROM tb_account
// WHERE user_name LIKE '%michael%'
// SQL:
// SELECT * FROM tb_account
// WHERE user_name LIKE '%michael%'
```
@ -262,9 +262,9 @@ QueryWrapper queryWrapper = QueryWrapper.create()
select(ARTICLE.ACCOUNT_ID).from(ARTICLE).where(ARTICLE.ID.ge(100))
));
// SQL:
// SQL:
// SELECT * FROM tb_account
// WHERE id >=
// WHERE id >=
// (SELECT account_id FROM tb_article WHERE id >= ? )
```
@ -281,11 +281,11 @@ QueryWrapper queryWrapper=QueryWrapper.create()
)
);
// SQL:
// SELECT * FROM tb_account
// WHERE id >= ?
// SQL:
// SELECT * FROM tb_account
// WHERE id >= ?
// AND EXIST (
// SELECT 1 FROM tb_article WHERE id >= ?
// SELECT 1 FROM tb_article WHERE id >= ?
// )
```
@ -299,10 +299,10 @@ QueryWrapper queryWrapper = QueryWrapper.create()
.and(ACCOUNT.SEX.eq(1).or(ACCOUNT.SEX.eq(2)))
.or(ACCOUNT.AGE.in(18,19,20).and(ACCOUNT.USER_NAME.like("michael")));
// SQL:
// SELECT * FROM tb_account
// WHERE id >= ?
// AND (sex = ? OR sex = ? )
// SQL:
// SELECT * FROM tb_account
// WHERE id >= ?
// AND (sex = ? OR sex = ? )
// OR (age IN (?,?,?) AND user_name LIKE ? )
```
@ -314,8 +314,8 @@ QueryWrapper queryWrapper = QueryWrapper.create()
.from(ACCOUNT)
.groupBy(ACCOUNT.USER_NAME);
// SQL:
// SELECT * FROM tb_account
// SQL:
// SELECT * FROM tb_account
// GROUP BY user_name
```
@ -328,9 +328,9 @@ QueryWrapper queryWrapper = QueryWrapper.create()
.groupBy(ACCOUNT.USER_NAME)
.having(ACCOUNT.AGE.between(18,25));
// SQL:
// SELECT * FROM tb_account
// GROUP BY user_name
// SQL:
// SELECT * FROM tb_account
// GROUP BY user_name
// HAVING age BETWEEN ? AND ?
```
@ -343,7 +343,7 @@ QueryWrapper queryWrapper = QueryWrapper.create()
.orderBy(ACCOUNT.AGE.asc()
, ACCOUNT.USER_NAME.desc().nullsLast());
// SQL:
// SQL:
// SELECT * FROM tb_account
// ORDER BY age ASC, user_name DESC NULLS LAST
```
@ -358,10 +358,10 @@ QueryWrapper queryWrapper = QueryWrapper.create()
.innerJoin(ARTICLE).on(ACCOUNT.ID.eq(ARTICLE.ACCOUNT_ID))
.where(ACCOUNT.AGE.ge(10));
// SQL:
// SELECT * FROM tb_account
// LEFT JOIN tb_article ON tb_account.id = tb_article.account_id
// INNER JOIN tb_article ON tb_account.id = tb_article.account_id
// SQL:
// SELECT * FROM tb_account
// LEFT JOIN tb_article ON tb_account.id = tb_article.account_id
// INNER JOIN tb_article ON tb_account.id = tb_article.account_id
// WHERE tb_account.age >= ?
```
@ -376,30 +376,30 @@ QueryWrapper queryWrapper = QueryWrapper.create()
.limit(10)
.offset(20);
// MySql:
// MySql:
// SELECT * FROM `tb_account` ORDER BY `id` DESC LIMIT 20, 10
// PostgreSQL:
// PostgreSQL:
// SELECT * FROM "tb_account" ORDER BY "id" DESC LIMIT 20 OFFSET 10
// Informix:
// Informix:
// SELECT SKIP 20 FIRST 10 * FROM "tb_account" ORDER BY "id" DESC
// Oracle:
// SELECT * FROM (SELECT TEMP_DATAS.*,
// Oracle:
// SELECT * FROM (SELECT TEMP_DATAS.*,
// ROWNUM RN FROM (
// SELECT * FROM "tb_account" ORDER BY "id" DESC)
// TEMP_DATAS WHERE ROWNUM <=30)
// SELECT * FROM "tb_account" ORDER BY "id" DESC)
// TEMP_DATAS WHERE ROWNUM <=30)
// WHERE RN >20
// Db2:
// SELECT * FROM "tb_account" ORDER BY "id" DESC
// Db2:
// SELECT * FROM "tb_account" ORDER BY "id" DESC
// OFFSET 20 ROWS FETCH NEXT 10 ROWS ONLY
// Sybase:
// Sybase:
// SELECT TOP 10 START AT 21 * FROM "tb_account" ORDER BY "id" DESC
// Firebird:
// Firebird:
// SELECT * FROM "tb_account" ORDER BY "id" DESC ROWS 20 TO 30
```
@ -489,7 +489,7 @@ accountMapper.update(account);
```sql
update tb_account
set user_name = ?, sex = ? where id = ?
set user_name = ?, sex = ? where id = ?
#params: null,1,100
```
@ -511,7 +511,7 @@ public class Account {
private Map<String, Object> options;
//getter setter
public void addOption(String key, Object value) {
if (options == null) {
options = new HashMap<>();
@ -612,7 +612,7 @@ public class Account {
## 还有问题?
加入 QQ 交流群: 532992631
加入 QQ 交流群: 850176767
![](./docs/assets/images/qq_group.png)