github.com/kunlun-qilian/sqlx/v3@v3.0.0/builder/addition_join.go (about)

     1  package builder
     2  
     3  import (
     4  	"context"
     5  	"strings"
     6  )
     7  
     8  type JoinAddition struct{}
     9  
    10  func (JoinAddition) AdditionType() AdditionType {
    11  	return AdditionJoin
    12  }
    13  
    14  func Join(table SqlExpr, prefixes ...string) *join {
    15  	return &join{
    16  		prefix: strings.Join(prefixes, " "),
    17  		target: table,
    18  	}
    19  }
    20  
    21  func InnerJoin(table SqlExpr) *join {
    22  	return Join(table, "INNER")
    23  }
    24  
    25  func LeftJoin(table SqlExpr) *join {
    26  	return Join(table, "LEFT")
    27  }
    28  
    29  func RightJoin(table SqlExpr) *join {
    30  	return Join(table, "RIGHT")
    31  }
    32  
    33  func FullJoin(table SqlExpr) *join {
    34  	return Join(table, "FULL")
    35  }
    36  
    37  func CrossJoin(table SqlExpr) *join {
    38  	return Join(table, "CROSS")
    39  }
    40  
    41  var _ Addition = (*join)(nil)
    42  
    43  type join struct {
    44  	prefix         string
    45  	target         SqlExpr
    46  	joinCondition  SqlCondition
    47  	joinColumnList []*Column
    48  	JoinAddition
    49  }
    50  
    51  func (j join) On(joinCondition SqlCondition) *join {
    52  	j.joinCondition = joinCondition
    53  	return &j
    54  }
    55  
    56  func (j join) Using(joinColumnList ...*Column) *join {
    57  	j.joinColumnList = joinColumnList
    58  	return &j
    59  }
    60  
    61  func (j *join) IsNil() bool {
    62  	return j == nil || IsNilExpr(j.target) || (j.prefix != "CROSS" && IsNilExpr(j.joinCondition) && len(j.joinColumnList) == 0)
    63  }
    64  
    65  func (j *join) Ex(ctx context.Context) *Ex {
    66  	t := "JOIN "
    67  	if j.prefix != "" {
    68  		t = j.prefix + " " + t
    69  	}
    70  
    71  	e := Expr(t)
    72  
    73  	e.WriteExpr(j.target)
    74  
    75  	if !(IsNilExpr(j.joinCondition)) {
    76  		e.WriteExpr(ExprBy(func(ctx context.Context) *Ex {
    77  			ex := Expr(" ON ")
    78  			ex.WriteExpr(j.joinCondition)
    79  			return ex.Ex(ctx)
    80  		}))
    81  	}
    82  
    83  	if len(j.joinColumnList) > 0 {
    84  		e.WriteExpr(ExprBy(func(ctx context.Context) *Ex {
    85  			ex := Expr(" USING ")
    86  
    87  			ex.WriteGroup(func(e *Ex) {
    88  				for i := range j.joinColumnList {
    89  					if i != 0 {
    90  						ex.WriteQuery(", ")
    91  					}
    92  					ex.WriteExpr(j.joinColumnList[i])
    93  				}
    94  			})
    95  
    96  			return ex.Ex(ContextWithToggles(ctx, Toggles{
    97  				ToggleMultiTable: false,
    98  			}))
    99  		}))
   100  	}
   101  
   102  	return e.Ex(ctx)
   103  }