gitee.com/eden-framework/sqlx@v0.0.3/builder/alias.go (about)

     1  package builder
     2  
     3  import (
     4  	"context"
     5  )
     6  
     7  func Alias(expr SqlExpr, name string) *exAlias {
     8  	return &exAlias{
     9  		name:    name,
    10  		SqlExpr: expr,
    11  	}
    12  }
    13  
    14  type exAlias struct {
    15  	name string
    16  	SqlExpr
    17  }
    18  
    19  func (alias *exAlias) IsNil() bool {
    20  	return alias == nil || alias.name == "" || IsNilExpr(alias.SqlExpr)
    21  }
    22  
    23  func (alias *exAlias) Ex(ctx context.Context) *Ex {
    24  	return Expr("(?) AS ?", alias.SqlExpr, Expr(alias.name)).Ex(ContextWithToggles(ctx, Toggles{
    25  		ToggleNeedAutoAlias: false,
    26  	}))
    27  }
    28  
    29  func MultiMayAutoAlias(columns ...SqlExpr) *exMayAutoAlias {
    30  	return &exMayAutoAlias{
    31  		columns: columns,
    32  	}
    33  }
    34  
    35  type exMayAutoAlias struct {
    36  	columns []SqlExpr
    37  }
    38  
    39  func (alias *exMayAutoAlias) IsNil() bool {
    40  	return alias == nil || len(alias.columns) == 0
    41  }
    42  
    43  func (alias *exMayAutoAlias) Ex(ctx context.Context) *Ex {
    44  	e := Expr("")
    45  
    46  	RangeNotNilExpr(alias.columns, func(expr SqlExpr, i int) {
    47  		if i > 0 {
    48  			e.WriteString(", ")
    49  		}
    50  		e.WriteExpr(expr)
    51  	})
    52  
    53  	return e.Ex(ContextWithToggles(ctx, Toggles{
    54  		ToggleNeedAutoAlias: true,
    55  	}))
    56  }